WO2023112503A1

WO2023112503A1 - Exterior material, solid-state battery, and electronic device

Info

Publication number: WO2023112503A1
Application number: PCT/JP2022/039941
Authority: WO
Inventors: 伊佐夫玉置; 治彦森; 憲英藤本; 英樹井村
Original assignee: 株式会社村田製作所
Priority date: 2021-12-14
Filing date: 2022-10-26
Publication date: 2023-06-22

Abstract

The present invention provides an exterior material capable of suppressing infiltration of water vapor. The present invention provides an exterior material which includes a metal layer, a first thermoplastic resin layer located on a first main surface side of the metal layer, and a second thermoplastic resin layer located on a second main surface side of the metal layer, and in which the melting point of the first thermoplastic resin layer and the melting point of the second thermoplastic resin layer are both higher than 260°C.

Description

Exterior materials, as well as solid-state batteries and electronic devices

The present invention relates to exterior materials, as well as solid-state batteries and electronic devices. Specifically, the present invention relates to a sheath, a solid-state battery comprising the sheath, and an electronic device comprising the sheath.

The exterior material is provided to cover the electronic device and protect the electronic device. Examples of electronic devices protected by exterior materials include batteries, circuit boards, composite modules, and electronic components.

Batteries include secondary batteries that can be repeatedly charged and discharged. Secondary batteries that can be repeatedly charged and discharged have been used for various purposes. For example, secondary batteries are used as power sources for electronic devices such as smartphones and laptop computers.

In the secondary battery, a liquid electrolyte (electrolytic solution) such as an organic solvent has conventionally been used as a medium for moving ions. However, secondary batteries using an electrolytic solution have problems such as leakage of the electrolytic solution. Therefore, development of a solid battery having a solid electrolyte instead of a liquid electrolyte is underway.

Japanese Patent No. 6179576

Here, when a conventional exterior material having a laminate structure including a metal layer, resin layers positioned on both sides of the metal layer, and adhesive layers positioned between the metal layer and the resin layer is used. There is In this case, depending on the properties of the adhesive layer of the exterior material, there is a possibility that the adhesiveness of the adhesive layer cannot be maintained appropriately. Therefore, when the exterior material is provided so as to cover the periphery of an electronic device such as a solid-state battery, water vapor may enter the electronic device such as a solid-state battery through the adhesive layer.

The present invention is in view of such circumstances. An object of the present invention is to provide an exterior material capable of suppressing permeation of water vapor, and an electronic device such as a solid-state battery including the exterior material.

In one embodiment of the invention,
A metal layer, a first thermoplastic resin layer located on the first main surface side of the metal layer, and a second thermoplastic resin layer located on the second main surface side of the metal layer,
An exterior material is provided in which both the melting point of the first thermoplastic resin layer and the melting point of the second thermoplastic resin layer are higher than 260°C.

Also, in one embodiment of the present invention,
A battery element comprising a positive electrode layer, a negative electrode layer, and a solid electrolyte layer interposed between the positive electrode layer and the negative electrode layer; an exterior material covering the battery element; a conducting portion;
The exterior material comprises a metal layer, a first thermoplastic resin layer located on the first main surface side of the metal layer, and a second thermoplastic resin layer located on the second main surface side of the metal layer. a layer and
A solid battery is provided, which is an exterior material in which both the melting point of the first thermoplastic resin layer and the melting point of the second thermoplastic resin layer are higher than 260°C.

Furthermore, in one embodiment of the present invention,
An electronic device and an exterior material covering the electronic device,
The exterior material comprises a metal layer, a first thermoplastic resin layer located on the first main surface side of the metal layer, and a second thermoplastic resin layer located on the second main surface side of the metal layer. a layer and
The present invention relates to an electronic device which is an exterior material in which both the melting point of the first thermoplastic resin layer and the melting point of the second thermoplastic resin layer are higher than 260°C.

According to the exterior material according to one embodiment of the present invention, it is possible to suppress the infiltration of water vapor. Further, according to the solid-state battery and the electronic device according to one embodiment of the present invention, it is possible to suppress the infiltration of water vapor into the interior thereof.

FIG. 1 is a cross-sectional view schematically showing an exterior material according to one embodiment of the present invention. FIG. 2 is a schematic diagram showing the manufacturing process of the exterior material according to one embodiment of the present invention. FIG. 3 is a cross-sectional view schematically showing a solid-state battery according to one embodiment of the invention. FIG. 4 is a cross-sectional view schematically showing a solid-state battery according to one embodiment of the invention. FIG. 5 is a cross-sectional view schematically showing a solid-state battery according to one embodiment of the invention. FIG. 6 is a cross-sectional view schematically showing how the solid-state battery according to one embodiment of the present invention prevents water vapor intrusion. FIG. 7 is a cross-sectional view schematically showing a solid-state battery according to one embodiment of the invention. FIG. 8 is a perspective view schematically showing a solid-state battery according to one embodiment of the invention. FIG. 9 is a cross-sectional view schematically showing a solid-state battery (expanded state) according to one embodiment of the present invention. FIG. 10 is a cross-sectional view schematically showing a solid-state battery according to one embodiment (with sealant) of the present invention. FIG. 11 is a cross-sectional view schematically showing a solid-state battery according to another embodiment of the invention. FIG. 12 is a cross-sectional view schematically showing a solid-state battery according to another embodiment of the invention. FIG. 13 is a cross-sectional view schematically showing an electronic device according to one embodiment of the invention. FIG. 14 is a schematic diagram showing a manufacturing process of a solid-state battery according to one embodiment of the present invention. FIG. 15 is a cross-sectional view schematically showing a conventional exterior material. FIG. 16 is a cross-sectional view schematically showing a conventional solid-state battery. FIG. 17 is a perspective view schematically showing a conventional solid-state battery.

[Exterior material of the present invention]
Hereinafter, an exterior material according to one embodiment of the present invention will be described in detail. Although the description will be made with reference to the drawings as necessary, the illustrated contents are only schematically and exemplarily shown for understanding of the present invention, and the appearance, dimensional ratios, etc. may differ from the actual part.

FIG. 1 is a cross-sectional view schematically showing an exterior material according to one embodiment of the present invention.

As shown in FIG. 1, the exterior material 11 according to one embodiment of the present invention includes a metal layer 11b, a first thermoplastic resin layer 11a located on the first main surface side of the metal layer 11b, and a metal layer The second thermoplastic resin layer 11c located on the second main surface side of 11b is included, and both the melting point of the first thermoplastic resin layer 11a and the melting point of the second thermoplastic resin layer 11c are higher than 260°C. is also high. The “thermoplastic resin” referred to in this specification is a resin that can be softened by applying heat, solidified by cooling, and can be reversibly softened and solidified. The thermoplastic resin may be a resin having heat-sealing properties.

Conventionally, an adhesive layer was interposed between the resin layer and the adherend in order to join the adherend such as the resin layer and the metal layer. For example, the conventional exterior material 11' shown in FIG. may have an agent layer 11e'). In contrast, in the exterior material 11 of the present invention, the two

resin layers

11a and 11c located on the first main surface side and the second main surface side of the metal layer 11b both have thermoplasticity and It is a resin layer having a melting point higher than the mounting temperature upper limit (see FIG. 1).

In this case, compared to conventional exterior materials, two thermoplastic resin layers are provided so as to sandwich a metal layer and/or the properties of each thermoplastic resin layer (softening by applying heat and cooling Due to the softening of the resin surface due to heating, it follows the unevenness of the metal layer surface, and as a result, the contact area between the resin layer surface and the metal layer surface increases, and the metal layer surface and the functional groups of the thermoplastic resin layer can cause chemical bonding and/or physical bonding between the metal layer surface and the thermoplastic resin layer due to intermolecular forces. As a result, two thermoplastic resin layers and an adherend such as a metal layer positioned therebetween can be mutually bonded without necessarily using an adhesive layer. As a result, it is possible to maintain the shape of the outer package having a laminated structure without necessarily using an adhesive layer.

Therefore, compared with conventional exterior materials that require the use of an adhesive layer, water vapor may enter through the adhesive, and the present invention can prevent water vapor from entering the exterior materials themselves. becomes. As a result, in the case of providing an exterior material in which penetration of water vapor is suppressed so as to cover the periphery of an electronic device such as a solid-state battery, it is possible to suppress the penetration of water vapor into the electronic device such as the solid-state battery. In other words, the exterior material itself can function as a water vapor barrier film.

In one embodiment of the present invention, two thermoplastic resin layers and an adherend such as a metal layer positioned between them can be bonded to each other without necessarily using an adhesive layer. It is also possible to reduce the overall thickness of the material. In other words, when the exterior material is integrated with an electronic device such as a battery, it can contribute to reducing the size of the integrated product itself. Reducing the size of the integrated body itself can contribute to, for example, improving energy density or saving space.

In addition, in one embodiment of the present invention, since the adhesive layer is not necessarily used, the step of applying the adhesive layer and the step of curing the adhesive layer can be omitted. Therefore, the facing material of one embodiment of the present invention can be a low cost facing material.

The constituent elements of the exterior material according to one embodiment of the present invention will be specifically described below.

[Metal layer]
The metal layer 11b is, as shown in FIG. In other words, the metal layer 11b is a layer sandwiched between the first thermoplastic resin layer 11a and the second thermoplastic resin layer 11c. The metal layer 11b is a layer extending planarly. Since it is a layer extending planarly, the metal layer 11b has two main surfaces. Specifically, the metal layer 11b extends so that the first main surface of the metal layer 11b faces the second main surface of the metal layer 11b. As the metal layer 11b used for the exterior material 11, for example, a metal foil may be used. Metal layer 11b may be a layer that is substantially impermeable to water vapor and/or gases.

[First thermoplastic resin layer]
The first thermoplastic resin layer 11a is located on the first main surface side of the metal layer 11b, as shown in FIG. In other words, the first thermoplastic resin layer 11a is located on the first main surface among the main surfaces of the metal layer 11b. The term "positioned" as used herein may mean that the first thermoplastic resin layer 11a is provided in direct contact with the metal layer 11b, or that the first thermoplastic resin layer 11a is provided in contact with another layer. It may be indirectly provided on the first main surface via the first main surface. In other words, it means that there may or may not be another layer between the first thermoplastic resin layer 11a and the metal layer. The first thermoplastic resin layer 11a is used to protect the electronic device, specifically to prevent water vapor from entering from the outside (water vapor barrier layer) or to prevent damage to the electronic device. If necessary, the first thermoplastic resin layer 11a may also have chemical resistance, insulating properties, and the like.

The first thermoplastic resin layer 11a is a layer containing a thermoplastic resin as a main component. A thermoplastic resin is a resin that can be bonded to an adherend such as a metal layer by applying heat. A thermoplastic resin is a resin that can be softened by applying heat and solidified by cooling, and can reversibly repeat softening and solidifying. The first thermoplastic resin layer 11a may be made of thermoplastic resin only. The first thermoplastic resin layer 11a may be composed of a single layer, or may be composed of an integrated body composed of two or more layers. The thermoplastic resin may be a resin having heat-sealing properties.

The melting point of the first thermoplastic resin layer 11a is preferably higher than 260°C. The "melting point of the first thermoplastic resin layer" as used in the present invention may be, for example, the temperature at which the first thermoplastic resin layer 11a melts, and may be the melting point described in detail below. . Moreover, when the first thermoplastic resin layer 11a is composed of two or more layers, the melting point of the material used for these layers is preferably higher than 260.degree.

[Second thermoplastic resin layer]
The second thermoplastic resin layer 11c is located on the second main surface side of the metal layer 11b, as shown in FIG. In other words, the second thermoplastic resin layer 11c is located on the second main surface among the main surfaces of the metal layer 11b. The second thermoplastic resin layer 11c is located on the main surface side of the metal layer 11b, which is different from the main surface side on which the first thermoplastic resin layer 11a is located. The term "positioned" as used herein may mean that the second thermoplastic resin layer 11c is provided in direct contact with the metal layer 11b, or that the second thermoplastic resin layer 11c is provided in another layer. may be indirectly provided on the second main surface via the In other words, it means that there may or may not be another layer between the second thermoplastic resin layer 11c and the metal layer 11b. The second thermoplastic resin layer 11c is used to protect the electronic device, specifically to prevent water vapor from entering from the outside (water vapor barrier layer) or to prevent damage to the electronic device. If necessary, the second thermoplastic resin layer 11c may also have chemical resistance, insulating properties, and the like.

The second thermoplastic resin layer 11c is a layer containing a thermoplastic resin as a main component. The thermoplastic resin used for the second thermoplastic resin layer 11c is a resin having the same characteristics as the thermoplastic resin used for the first thermoplastic resin. The second thermoplastic resin layer 11c may be made of thermoplastic resin only. The second thermoplastic resin layer 11c may be a single layer, or may be composed of an integrated body composed of two or more layers.

The melting point of the second thermoplastic resin layer 11c is preferably higher than 260°C. The "melting point of the second thermoplastic resin layer" as used in the present invention may be, for example, the temperature at which the second thermoplastic resin layer 11c melts, but may be the melting point described in detail below. . Moreover, when the second thermoplastic resin layer 11c is composed of two or more layers, the melting point of the material used for these layers is preferably higher than 260.degree.

For the melting point of the first thermoplastic resin layer 11a and the melting point of the second thermoplastic resin layer 11c, values measured by a conventionally known method may be used. For example, the melting point of the first thermoplastic resin layer 11a and the melting point of the second thermoplastic resin layer 11c may be values determined according to the method described in JIS K7121-2012.

The melting point of the first thermoplastic resin layer 11a and the melting point of the second thermoplastic resin layer 11c can be controlled by a conventionally known method. For example, the melting point of the first thermoplastic resin layer 11a and the melting point of the second thermoplastic resin layer 11c are the molecular weight, polymerization degree, molecular weight distribution, crystallinity degree, copolymerization ratio, and And it can be controlled by adjusting the size of the polymer crystal.

The melting point of the first thermoplastic resin layer 11a is not particularly limited as long as the first thermoplastic resin layer 11a does not melt at the mounting temperature when mounting the electronic device provided with the exterior material of the present invention on a substrate or the like. From the viewpoint of further preventing the first thermoplastic resin layer 11a from melting at the mounting temperature, the melting point of the first thermoplastic resin layer 11a is preferably 270°C or higher, more preferably 280°C or higher, and still more preferably 290°C. That's all there is to it. On the other hand, if the melting point of the first thermoplastic resin layer 11a is too high, the first thermoplastic resin layer 11a is difficult to soften, making it difficult to process. Become. From the viewpoint of improving workability and/or reducing manufacturing costs, the melting point of the first thermoplastic resin layer 11a may be preferably 400° C. or lower, more preferably 370° C. or lower, and still more preferably 350° C. or lower. Especially preferably, it may be 330° C. or lower.

The melting point of the second thermoplastic resin layer 11c is not particularly limited as long as the second thermoplastic resin layer 11c does not melt at the mounting temperature when mounting the electronic device provided with the exterior material of the present invention on a substrate or the like. From the viewpoint of further preventing the second thermoplastic resin layer 11c from melting at the mounting temperature, the melting point of the second thermoplastic resin layer 11c is preferably 270°C or higher, more preferably 280°C or higher, and still more preferably 290°C. That's all there is to it. On the other hand, when the melting point of the second thermoplastic resin layer 11c is too high, the second thermoplastic resin layer 11c becomes difficult to soften, making it difficult to process. Become. From the viewpoint of improving workability or reducing manufacturing costs, the melting point of the second thermoplastic resin layer 11c may be preferably 400° C. or lower, more preferably 370° C. or lower, still more preferably 350° C. or lower, and particularly preferably 350° C. or lower. may be 330° C. or lower.

From the viewpoint of further reducing the size of an integrated product obtained when the exterior material is integrated with an electronic device such as a battery, the thickness of the exterior material 11 is preferably 1 μm or more and 500 μm or less, more preferably 5 μm or more and 300 μm. It is more preferably 10 μm or more and 200 μm or less, and particularly preferably 20 μm or more and 150 μm.

The thickness of the metal layer 11b may be, for example, 1 μm or more and 200 μm or less. From the viewpoint of further reducing the total thickness of the exterior material 11, the thickness of the metal layer 11b may be 1 μm or more and 100 μm or less, preferably 10 μm or more and 100 μm or less, more preferably 10 μm or more and 50 μm or less, and still more preferably 20 μm or more and 50 μm or less. can be

The thickness of the first thermoplastic resin layer 11a is preferably 1 μm or more and 500 μm or less, more preferably 2 μm or more and 300 μm or less, still more preferably 3 μm or more and 100 μm or less, from the viewpoint of further reducing the total thickness of the exterior material 11. can be

The thickness of the second thermoplastic resin layer 11c is preferably 1 μm or more and 500 μm or less, more preferably 2 μm or more and 300 μm or less, still more preferably 3 μm or more and 100 μm or less, from the viewpoint of further reducing the total thickness of the exterior material 11. can be

In the exterior material 11 according to one embodiment of the present invention, even if there is another layer between the metal layer 11b and the first thermoplastic resin layer 11a located on the first main surface side of the metal layer 11b, There may well be another layer between the second thermoplastic resin layer 11c located on the second main surface side of the metal layer 11b. Such other layers and further layers may be, for example, water vapor barrier layers, insulating layers, chemical resistant layers, heat resistant layers, or damage prevention layers.

The exterior material 11 according to one embodiment of the present invention may have a first sub-layer covering the first thermoplastic resin layer 11a, and may have a second sub-layer covering the second thermoplastic resin layer 11c. good too. Specifically, on the main surface of the first thermoplastic resin layer 11a different from the main surface of the first thermoplastic resin layer 11a facing or in contact with the first main surface of the metal layer 11b There may be a first sublayer. In one such embodiment, the first thermoplastic layer is located between the first sublayer and the metal layer. A second sub-layer is formed on the major surface of the second thermoplastic resin layer 11c that is different from the major surface of the second thermoplastic resin layer 11c facing or in contact with the second major surface of the metal layer 11b. There may be. In one such embodiment, a second thermoplastic layer is located between the second sub-layer and the metal layer. Such first and second sub-layers may be, for example, additional water vapor barrier layers, chemical resistant layers, heat resistant cladding, or damage resistant layers. Specifically, for example, it may be an additional metal layer or a metal plating layer formed by sputtering or the like.

As described in the above effect, the exterior material 11 according to one embodiment of the present invention does not use an adhesive layer or uses a relatively thin adhesive layer from the viewpoint of suppressing the infiltration of water vapor. may be used. When the adhesive layer is not used, there is no concern that water vapor may enter through the adhesive layer, so the water vapor barrier properties of the exterior material can be improved. Furthermore, by using a material with a melting point higher than 260° C., it is possible to provide an exterior that can withstand solder mounting. When using an adhesive with a relatively thin thickness, the adhesive may be, for example, an adhesive that can maintain adhesive strength before and after the mounting process.

The exterior material according to one embodiment of the present invention may adopt the following aspects.

In one embodiment of the present invention, at least one of the first thermoplastic resin layer 11a and the second thermoplastic resin layer 11c may be directly bonded to the metal layer 11b.

Direct bonding between the thermoplastic resin layer and the metal layer 11b means that the thermoplastic resin layer and the metal layer 11b are directly bonded without any other layer interposed between the thermoplastic resin layer and the metal layer 11b. It means that they are connected to each other. As such an embodiment, for example, the thermoplastic resin layer and the metal layer 11b are directly bonded to each other without an adhesive layer interposed between the thermoplastic resin layer and the metal layer 11b. Things are mentioned. The term "joining" as used herein means, for example, that in a state in which two objects are in contact with each other, the two objects in contact with each other do not separate from each other unless a force is applied to the two objects from the outside. do. As for the directly bonded layer, for example, the first thermoplastic resin layer 11a and the metal layer 11b may be directly bonded to each other, or the second thermoplastic resin layer 11c and the metal layer 11b may be directly bonded to each other. may be From the viewpoint of further suppressing the penetration of water vapor, both the first thermoplastic resin layer 11a and the second thermoplastic resin layer 11c may be directly bonded to the metal layer 11b.

Direct bonding between the thermoplastic resin layer and the metal layer 11b may be achieved by, for example, pressing the thermoplastic resin layer and the metal layer 11b together. Crimping means bonding the thermoplastic resin layer and the metal layer 11b by pressurizing or compressing at least one of the thermoplastic resin layer and the metal layer 11b. For example, crimping is performed by superimposing the first thermoplastic resin layer 11a and the metal layer 11b and applying a force so as to sandwich the superimposed first thermoplastic resin layer 11a and the metal layer 11b. may be made by When the second thermoplastic resin layer 11c and the metal layer 11b are press-bonded together, the same method as described above may be used. When directly bonding the thermoplastic resin layer and the metal layer 11b, an adhesive layer may not be used. The thermoplastic resin layer used for the exterior material itself has adhesiveness. Therefore, the thermoplastic resin layer and the metal layer 11b can be adhered without using an adhesive layer. Although the mechanism by which the thermoplastic resin layer itself has a binding force is not clear, for example, the molecular structure that contributes to the binding force contained in the thermoplastic resin, or the functional group in the molecule, or the thermoplastic resin is the adherend. It is considered that the reason is that it enters into the fine unevenness of the surface.

The difference between the melting point of the first thermoplastic resin layer 11a and the melting point of the second thermoplastic resin layer 11c may be 20°C or more. Specifically, the melting point of the first thermoplastic resin layer 11a may be higher than the melting point of the second thermoplastic resin layer 11c by 20° C. or more, and the melting point of the first thermoplastic resin layer 11a may be the second heat. It may be 20° C. or more lower than the melting point of the plastic resin layer 11c. When the difference between the melting point of the first thermoplastic resin layer 11a and the melting point of the second thermoplastic resin layer 11c is 20° C. or more, the exterior material 11 can be easily manufactured. Specifically, in the manufacturing method of the exterior material 11 described later, a thermoplastic resin layer having a relatively high melting point is thermally laminated on the first main surface side of the metal layer 11b, and then the second main surface of the metal layer 11b is laminated. It becomes possible to thermally laminate a thermoplastic resin layer having a relatively low melting point on the face side.

The difference between the melting point of the first thermoplastic resin layer 11a and the melting point of the second thermoplastic resin layer 11c is preferably 25° C. or more, more preferably 30° C., from the viewpoint of facilitating the manufacture of the exterior material 11. above, more preferably 35° C. or higher, particularly preferably 40° C. or higher. On the other hand, from the viewpoint of facilitating temperature control during thermal lamination and/or cooling during manufacturing of the exterior material 11, the melting point of the first thermoplastic resin layer 11a and the melting point of the second thermoplastic resin layer 11c The difference may be 100°C or less, preferably 80°C or less, more preferably 70°C or less, even more preferably 60°C or less, particularly preferably 50°C or less.

The types of the metal layer, the first thermoplastic resin, and the second thermoplastic resin that can be used for the exterior material according to one embodiment of the present invention are described below.

[Type of metal layer]
Examples of the metal material forming the metal layer 11b include at least one selected from the group consisting of aluminum (or its alloy), stainless steel, copper, nickel, titanium, nickel-plated steel plate, and the like. A commercial product can be used for the metal layer 11b.

When aluminum (or its alloy) is used for the metal layer 11b, for example, an aluminum material that has been used in the past may be used. When an aluminum alloy is used for the metal layer 11b, for example, an aluminum alloy having a composition specified by JIS A8021 or JIS 8079 may be used.

[Types of First Thermoplastic Resin Layer and Second Thermoplastic Resin Layer]
The thermoplastic resin used for the first thermoplastic resin layer 11a and the second thermoplastic resin layer 11c is not particularly limited as long as the melting point exceeds 260° C. For example, liquid crystal polymer, aromatic polyester resin ( polyethylene naphthalate), aromatic polyether ketone resins, fluorine resins, polyphenylene sulfide resins, polyamide resins, thermoplastic polyimide resins, polyamideimide resins, polyetherimide resins, phenolic resins, acrylic resins Resins, polyurethane resins, silicone resins, or modified products thereof may be used. Also, resins classified as super engineering plastics may be used. The first thermoplastic resin layer 11a and the second thermoplastic resin layer 11c may be homopolymers or copolymers of the above resins. For the first thermoplastic resin layer 11a and the second thermoplastic resin layer 11c, the above resin may be used as a single product, or a compound product configured by combining two or more types of resin may be used. The first thermoplastic resin layer 11a and the second thermoplastic resin layer 11c may be a single layer, or may be composed of two or more layers. Commercially available products can be used for the first thermoplastic resin layer 11a and the second thermoplastic resin layer 11c.

Among the above resins, the first thermoplastic resin layer 11a and the second thermoplastic resin layer 11c are composed of liquid crystal polymer, polyethylene naphthalate, aromatic polyether ketone resin, and fluorine resin, from the viewpoint of further suppressing the infiltration of water vapor. may be composed of at least one resin selected from the group consisting of system resins, polyamide system resins, and polyphenylene sulfide system resins.

Liquid crystal polymers include thermotropic liquid crystal polymers that exhibit liquid crystallinity in a molten state and rheotropic liquid crystal polymers that exhibit liquid crystallinity in a solution state. Although any liquid crystal polymer may be used in the present invention, a thermotropic liquid crystal polymer may be used from the viewpoint of further suppressing the penetration of water vapor and/or from the viewpoint of preventing melting at the reflow temperature.

Among thermotropic liquid crystal polymers, thermotropic liquid crystal polyester (hereinafter simply referred to as “liquid crystal polyester”) is, for example, an aromatic hydroxycarboxylic acid as an essential monomer, and an aromatic dicarboxylic acid, an aromatic diol, or the like. It is an aromatic polyester obtained by reacting with a monomer and exhibits liquid crystallinity when melted. Representative examples include Type I [formula (1) below] synthesized from parahydroxybenzoic acid (PHB), phthalic acid, and 4,4'-biphenol, PHB and 2,6-hydroxynaphthoic acid. Type II [formula (2)] synthesized from PHB, terephthalic acid, and type III [formula (3)] synthesized from ethylene glycol.

As the liquid crystal polymer used for the exterior material, type I liquid crystal polyester and type II liquid crystal polyester among the above may be used because they are superior in heat resistance and hydrolysis resistance.

Aromatic polyester-based resins are based on an aromatic dicarboxylic acid component and a glycol component. In the present invention, in particular, an aromatic polyester resin having a basic skeleton of a naphthalene dicarboxylic acid component and an alkylene glycol component may be used, and specifically polyethylene naphthalate may be used. As the polyethylene naphthalate, polyethylene naphthalate obtained by reacting 2,6-naphthalenedicarboxylic acid or 2,7-naphthalenedicarboxylic acid as the naphthalenedicarboxylic acid component and ethylene glycol as the alkylene glycol component is used. good too.

Aromatic polyether ketone resin is a resin that has a structure in which a ketone group and an ether group are linked to an aromatic ring. There are various types of aromatic polyether ketone resins depending on the arrangement order and number of aromatic rings, ketone groups, and ether groups in the constituent repeating units. may Specifically, in the present invention, examples of aromatic polyetherketone-based resins include polyketone (PK), polyetherketone (PEK), polyetheretherketone (PEEK), polyetherketoneketone (PEKK), and polyallyl ether. Ketone (PAEK), polyetherketoneetherketoneketone (PEKEKK), or the like may also be used.

A fluororesin is a resin obtained by polymerizing an olefin containing fluorine. As the fluororesin, polyethylene terephthalate (PETF), perfluoroalkoxyalkane (PFA), perfluoroethylene propene copolymer (FEP), ethylenetetrafluoroethylene copolymer (ETFE), and the like may be used.

Polyphenylene sulfide is a resin that contains aromatic rings and sulfide bonds in the structural repeating units of the polymer. Polyphenylene sulfide includes a linear type, a cross-linked type, a semi-cross-linked type, and the like, and any type may be used.

A polyamide resin is a resin that has a basic skeleton of a diamine component and a carboxylic acid component, and contains an amide bond in the structural repeating unit of the polymer. In the present invention, as the polyamide-based resin, an aromatic polyamide-based resin having a relatively high melting point may be used, or a highly heat-resistant polyamide (HTPA)-based resin may be used.

The resin used for the first thermoplastic resin layer 11a and the second thermoplastic resin layer 11c may be a crystalline resin or an amorphous resin. From the viewpoint of suppressing permeation of water vapor, a crystalline resin that generally does not allow water vapor to permeate may be used.

The first thermoplastic resin layer 11a and the second thermoplastic resin layer 11c may contain filler. The filler may be, for example, carbon fiber, glass fiber, silica, talc, inorganic particles, or the like. The filler may be contained in the first thermoplastic resin layer 11a in an amount of, for example, 50% by volume or less, and may be contained in the second thermoplastic resin layer 11c in an amount of, for example, 50% by volume or less.

In the exterior material according to one embodiment of the present invention, the first thermoplastic resin layer 11a and the second thermoplastic resin layer 11c may be made of the same type of thermoplastic resin. By adopting such a configuration, since the same type of material is handled, it becomes easier to unify the equipment and the like for manufacturing the exterior material 11, which can contribute to the improvement of manufacturing efficiency. As used herein, the term "species" of "the same species" means the type of polymeric material determined based on the repeating units of the molecular structure of the polymer and/or the properties of the polymeric material. For example, "the first thermoplastic resin layer 11a and the second thermoplastic resin layer 11c are made of the same type of thermoplastic resin" means that the first thermoplastic resin is a liquid crystal polymer exhibiting liquid crystallinity. is selected, it means that a liquid crystal polymer exhibiting liquid crystallinity is also selected as the second thermoplastic resin. For example, when an aromatic polyester-based resin that is a polyester type containing an aromatic ring is selected as the first thermoplastic resin, an aromatic polyester-based resin that is a polyester type containing an aromatic ring is selected as the second thermoplastic resin. means it is selected. For example, when an aromatic polyether ketone-based resin, which is a polymer species containing an aromatic ring, an ether bond, and a ketone group, is selected as the first thermoplastic resin, the second thermoplastic resin is an aromatic ring, an ether bond, , and an aromatic polyetherketone-based resin, which is a polymer species containing ketone groups.

If the first thermoplastic resin layer 11a and the second thermoplastic resin layer 11c are made of the same type of thermoplastic resin, the first thermoplastic resin layer 11a and the second thermoplastic resin layer 11c properties may be different. For example, when the first thermoplastic resin layer 11a and the second thermoplastic resin layer 11c are made of the same type of thermoplastic resin, the first thermoplastic resin layer 11a and the second thermoplastic resin layer 11a Thermal properties (e.g. melting point, coefficient of thermal expansion, thermal conductivity), mechanical properties (e.g. tensile strength, flexural strength, compressive strength), resistivity, chemical resistance, etc. of layer 11c are different. good.

From the viewpoint of further improving manufacturing efficiency, the first thermoplastic resin layer 11a and the second thermoplastic resin layer 11c may be made of the same thermoplastic resin material. The “same material” as used herein means a material having the same repeating unit of the molecular structure of the polymer. For example, when polyethylene naphthalate composed of repeating units of naphthalene dicarboxylic acid and ethylene glycol is selected as the first thermoplastic resin, the second thermoplastic resin is polyethylene composed of similar repeating units. It means that naphthalate is selected. For example, when polyether ether ketone, in which an ether bond, an ether bond, and a ketone group appear in this order as repeating units, is selected as the first thermoplastic resin, the second thermoplastic resin is also composed of similar repeating units. This means that the polyetheretherketone that is used is selected.

If the first thermoplastic resin layer 11a and the second thermoplastic resin layer 11c are made of the same thermoplastic resin material, the first thermoplastic resin layer 11a and the second thermoplastic resin layer 11c properties may be different. For example, when the first thermoplastic resin layer 11a and the second thermoplastic resin layer 11c are made of the same thermoplastic resin, the first thermoplastic resin layer 11a and the second thermoplastic resin Thermal properties (e.g. melting point, coefficient of thermal expansion, thermal conductivity), mechanical properties (e.g. tensile strength, flexural strength, compressive strength), resistivity, chemical resistance, etc. of layer 11c are different. good.

(Method for manufacturing exterior material of the present invention)
A method for manufacturing an exterior material according to an embodiment of the present invention will be described below. A method for manufacturing an exterior material according to an embodiment of the present invention roughly includes the following steps (i) and (ii) in order (see FIG. 2).

(i) The metal layer 511b and the first thermoplastic resin material 511a are placed on the first heating roll 401 and the first cooling roll so that the first thermoplastic resin material 511a is positioned on the first main surface of the metal layer 511b. 501;
(ii) The metal layer 511b and the first thermoplastic resin material are placed on the second heating roll 402 and the second cooling roll 502 so that the second thermoplastic resin material 511c is positioned on the second main surface of the metal layer 511b. The process of passing through.

First, the first thermoplastic resin material 511a is adhered to the first main surface of the metal layer 511b by thermal lamination. Specifically, the metal layer 511b and the first thermoplastic resin material 511a are placed together with the first heating roll 401 so that the first main surface of the metal layer 511b and the first thermoplastic resin material 511a overlap each other. Pass between the cooling roll 501 . At this time, the metal layer 511b is brought into contact with the first heating roll 401, and the first thermoplastic resin material 511a is brought into contact with the first cooling roll 501. Then, as shown in FIG. As a result, the portion of the first thermoplastic resin material 11a in contact with the heated metal layer 511b is softened, and the softened first thermoplastic resin material 511a is adhered (thermally fused) to the metal layer 511b. After that, from between the first heating roll 401 and the first cooling roll 501, an integrated product of the metal layer 511b and the first thermoplastic resin material 511a is obtained.

Next, the integrated product of the metal layer 511b and the first thermoplastic resin material 511a is bonded with the second thermoplastic resin material 511c to the remaining second main surface of the metal layer 511b by thermal lamination. Specifically, the metal layer 511b and the second thermoplastic resin material 511c are placed together with the second heating roll 402 so that the remaining second main surface of the metal layer 511b and the second thermoplastic resin material 511c overlap each other. Pass between the second cooling roll 502 . As a result, the portion of the second thermoplastic resin material 511c in contact with the heated metal layer 511b is softened, and the softened second thermoplastic resin material 511c is bonded (heat-sealed) to the metal layer 511b. At this time, the metal layer 511b is brought into contact with the second heating roll 402, and the second thermoplastic resin material 511c is brought into contact with the second cooling roll 502. Then, as shown in FIG. From between the rolls of the second heating roll 402 and the second cooling roll 502, the exterior material 11 according to one embodiment of the present invention is obtained.

In the present invention, the melting point of the thermoplastic resin material to be heat-sealed first is preferably 20°C or more higher than the melting point of the thermoplastic resin material to be heat-sealed subsequently. The thermoplastic resin material that is heat-sealed first is called the first thermoplastic resin material, and the thermoplastic resin material that is heat-sealed next is called the second thermoplastic resin material. In other words, the melting point of the first thermoplastic resin material is preferably higher than the melting point of the second thermoplastic resin material. More preferably, the melting point of the first thermoplastic resin material is 20° C. or more higher than the melting point of the second thermoplastic resin material.

According to the above manufacturing method, when the thermoplastic resin material having a relatively low melting point is thermally laminated on the second main surface side of the metal layer 511b later, the first main surface side of the metal layer 511b is preceded by The relatively high melting point thermoplastic material that is heat laminated cannot soften and remains adhered to the metal layer. For this reason, a thermoplastic resin material having a relatively high melting point is thermally laminated to the first main surface side of the metal layer 511b, and then a relatively low melting point thermoplastic resin material is laminated to the second main surface side of the metal layer 511b. It becomes possible to thermally laminate a thermoplastic resin material. In the above-described mode, the temperature of the first heating roll 401 that thermally laminates the metal layer and the resin material first is preferably higher than that of the subsequent second heating roll 402 .

When using an adhesive layer, the adhesive layer may be provided in advance on the metal layer 511b and/or the thermoplastic resin layer.

The temperature of the first heating roll 401 is not particularly limited as long as the metal layer 511b and the first thermoplastic resin material 511a can be heat-sealed. C. or less, more preferably 230.degree. C. or higher and 350.degree. C. or lower, still more preferably 230.degree.

The temperature of the second heating roll 402 is not particularly limited as long as the metal layer 511b and the second thermoplastic resin material 511c can be heat-sealed. C. or less, more preferably 230.degree. C. or higher and 350.degree. C. or lower, still more preferably 230.degree.

[Electronic device]
An electronic device to which the exterior material according to one embodiment of the present invention can be applied will be described below. Although the description will be made with reference to the drawings as necessary, the illustrated contents are only schematically and exemplarily shown for understanding of the present invention, and the appearance, dimensional ratios, etc. may differ from the actual part.

The electronic device to which the exterior material according to one embodiment of the present invention can be applied is not particularly limited except for using the exterior material according to one embodiment of the present invention. Examples of electronic devices here include circuit boards, composite modules, batteries, and electronic parts. Batteries include secondary batteries, particularly solid-state batteries. Electronic components include capacitors, resistors, coils, diodes, filters, oscillators and/or transistors, and the like. Electronic device elements other than exterior materials (e.g., batteries refer to terminals, electrodes, separators, electrolytes, etc., and capacitors refer to electrodes, dielectrics, terminals, etc.) apply to electronic devices. There is no particular limitation as long as it is For example, such electronic device elements may be pre-existing.

An embodiment of the present invention includes an electronic device and an exterior material covering the electronic device. The exterior material includes a metal layer, a first thermoplastic resin layer located on the first main surface side of the metal layer, and a second thermoplastic resin layer located on the second main surface side of the metal layer. wherein both the melting point of the first thermoplastic resin layer and the melting point of the second thermoplastic resin layer are higher than 260°C.

As described in the characteristics of the exterior material, the exterior material according to one embodiment of the present invention can suppress permeation of water vapor into the exterior material itself. As a result, in the case of providing an exterior material that suppresses permeation of water vapor so as to cover the periphery of the electronic device, it is possible to suppress permeation of water vapor into the electronic device.

In addition, in one embodiment of the present invention, two thermoplastic resin layers and an adherend such as a metal layer positioned between them can be bonded to each other without necessarily using an adhesive layer. It is also possible to reduce the overall thickness of the material. That is, in the case where the exterior material is integrated with an electronic component or an electronic device, it can contribute to the reduction of the size of the integrated product itself. By reducing the size of the integrated body itself, it is possible to contribute to space saving and the like.

In addition, in one embodiment of the present invention, since the adhesive layer is not necessarily used, the step of applying the adhesive layer and the step of curing the adhesive layer can be omitted. Moreover, it is possible to provide an electronic device that can be solder-mounted without using an expensive ceramic package. Therefore, the electronic device of one embodiment of the present invention can be a low-cost electronic device.

[Solid battery]
In the following, a battery, particularly a solid-state battery, is taken as an example of the electronic device, and a case where the exterior material according to one embodiment of the present invention is applied to the solid-state battery will be described in detail. Specifically, the exterior material is applied so as to cover the battery elements of the solid-state battery. In this case, since the internal battery element is protected from the external environment, the solid battery can be packaged as a whole. That is, a solid battery with an exterior material can also be called a solid battery package. 3 to 12 schematically show the form in which the battery element 100 is covered with the exterior material according to one embodiment of the present invention, but the exterior material according to one embodiment of the present invention can be applied to a battery other than a solid battery. When applied to the electronic device, the battery element 100 in the above drawings may be used as the electronic device element.

A solid-state battery to which the exterior material according to one embodiment of the present invention is applied is not particularly limited except for using the exterior material according to one embodiment of the present invention. Specifically, battery elements (eg, electrodes, solid electrolytes, conductive parts, etc.) other than the exterior material are not particularly limited as long as they are applied to solid batteries. For example, such battery elements may be conventional.

(Basic configuration of solid-state battery)
The basic configuration of the solid-state battery will be described below. A solid battery comprises at least positive and negative electrode layers and a solid electrolyte. Specifically, a solid battery has a battery element including a battery structural unit composed of a positive electrode layer, a negative electrode layer, and a solid electrolyte interposed therebetween.

The term "solid battery" as used in the present invention broadly refers to a battery whose components are composed of solids, and in terms of discussion, the battery components (particularly preferably all battery components) are composed of solids. It refers to an all-solid-state battery that In a preferred embodiment, the solid-state battery in the present invention is a stacked-type solid-state battery configured such that each layer forming a battery structural unit is stacked with each other, and each such layer is preferably made of a sintered body. The term "solid battery" includes not only a so-called "secondary battery" that can be repeatedly charged and discharged, but also a "primary battery" that can only be discharged. According to one preferred aspect of the invention, the "solid battery" is a secondary battery. "Secondary battery" is not limited to its name, and can include, for example, power storage devices.

The term "cross-sectional view" as used in this specification refers to a state when viewed from a direction substantially perpendicular to the thickness direction of the battery element that constitutes the solid-state battery. "Up-down direction" and "left-right direction" used directly or indirectly in this specification correspond to the up-down direction and left-right direction in the drawings, respectively. Unless otherwise specified, the same reference numerals or symbols indicate the same members/parts or the same meanings. In a preferred embodiment, the downward vertical direction (that is, the direction in which gravity acts) corresponds to the "downward direction", and the opposite direction corresponds to the "upward direction".

In the solid battery, each layer that constitutes it may be formed by firing, or the positive electrode layer, negative electrode layer, solid electrolyte, etc. may form a sintered layer. Preferably, the positive electrode layer, the negative electrode layer and the solid electrolyte are each integrally sintered with each other, so that the battery element may form an integral sintered body.

The positive electrode layer is an electrode layer containing at least a positive electrode active material. The positive electrode layer may further comprise a solid electrolyte. For example, the positive electrode layer is composed of a sintered body containing at least positive electrode active material particles and solid electrolyte particles. In one aspect, the positive electrode layer is composed of a sintered body that substantially contains only positive electrode active material particles and solid electrolyte particles. On the other hand, the negative electrode layer is an electrode layer containing at least a negative electrode active material. The negative electrode layer may further comprise a solid electrolyte. For example, the negative electrode layer is composed of a sintered body containing at least negative electrode active material particles and solid electrolyte particles. In one aspect, the negative electrode layer is composed of a sintered body that substantially contains only negative electrode active material particles and solid electrolyte particles.

The positive electrode active material and negative electrode active material are substances involved in the transfer of electrons in solid-state batteries. Ions are transferred (conducted) between the positive electrode layer and the negative electrode layer via the solid electrolyte, and electrons are transferred, whereby charging and discharging are performed. The positive electrode layer and the negative electrode layer may in particular be layers capable of intercalating and deintercalating lithium ions or sodium ions. That is, the solid-state battery may be an all-solid-state secondary battery in which lithium ions or sodium ions move between the positive electrode layer and the negative electrode layer via a solid electrolyte to charge and discharge the battery.

(Positive electrode active material)
Examples of the positive electrode active material contained in the positive electrode layer include a lithium-containing phosphate compound having a Nasicon type structure, a lithium-containing phosphate compound having an olivine type structure, a lithium-containing layered oxide, and a lithium-containing compound having a spinel type structure. At least one selected from the group consisting of oxides and the like can be mentioned. _Li3V2 ( _PO4 ) ₃ etc. are mentioned as an example of the _lithium containing phosphate compound which has a Nasicon type structure. Examples of lithium-containing phosphate compounds having an olivine _structure include _Li3Fe2 ( _PO4 ) ₃ , _LiFePO4 , and/or _LiMnPO4 . Examples of lithium-containing layered oxides include LiCoO ₂ and LiCo _1/3 Ni _1/3 Mn _1/3 O ₂ . Examples of lithium-containing oxides having a spinel structure include LiMn ₂ O ₄ and/or LiNi _0.5 Mn _1.5 O ₄ . Although the type of lithium compound is not particularly limited, for example, a lithium transition metal composite oxide and a lithium transition metal phosphate compound may be used. Lithium transition metal composite oxide is a general term for oxides containing lithium and one or more transition metal elements as constituent elements, and lithium transition metal phosphate compounds are lithium and one or more transition metal elements. is a general term for phosphoric acid compounds containing transition metal elements as constituent elements. The types of transition metal elements are not particularly limited, but examples include cobalt (Co), nickel (Ni), manganese (Mn) and iron (Fe).

Examples of positive electrode active materials capable of occluding and releasing sodium ions include sodium-containing phosphate compounds having a Nasicon-type structure, sodium-containing phosphate compounds having an olivine-type structure, sodium-containing layered oxides, and sodium-containing compounds having a spinel-type structure. At least one selected from the group consisting of oxides and the like can be mentioned. For example, in the case of sodium-containing phosphate compounds, _Na3V2 ( _PO4 ) ₃ , _NaCoFe2 ₍ _PO4 ₎ ₃ _, _Na2Ni2Fe ( _PO4 ) ₃ , _Na3Fe2 ( _PO4 ) ₃ , Na ₂ FeP ₂ O ₇ , Na ₄ Fe ₃ (PO ₄ ) ₂ (P ₂ O ₇ ), and at least one selected from the group consisting of NaFeO ₂ as the sodium-containing layered oxide.

In addition, the positive electrode active material may be, for example, an oxide, a disulfide, a chalcogenide, or a conductive polymer. The oxide may be, for example, titanium oxide, vanadium oxide, manganese dioxide, or the like. Disulfides are, for example, titanium disulfide or molybdenum sulfide. The chalcogenide may be, for example, niobium selenide. The conductive polymer may be, for example, disulfide, polypyrrole, polyaniline, polythiophene, polyparastyrene, polyacetylene, polyacene, or the like.

(Negative electrode active material)
Examples of the negative electrode active material contained in the negative electrode layer include oxides containing at least one element selected from the group consisting of Ti, Si, Sn, Cr, Fe, Nb and Mo, carbon materials such as graphite, and graphite-lithium. at least one selected from the group consisting of compounds, lithium alloys, lithium-containing phosphate compounds having a Nasicon-type structure, lithium-containing phosphate compounds having an olivine-type structure, and lithium-containing oxides having a spinel-type structure. be done. Examples of lithium alloys include Li—Al and the like. _Li3V2 ( _PO4 ) ₃ and/or LiTi2( _PO4 ) ₃ etc. are mentioned as an example of the _lithium containing phosphate compound which has a Nasicon type structure. Examples of lithium-containing phosphate compounds having an olivine _structure include _Li3Fe2 ( _PO4 ) ₃ and/or _LiCuPO4 . An example of a lithium-containing oxide having a spinel structure includes Li ₄ Ti ₅ O ₁₂ and the like.

The negative electrode active material capable of absorbing and releasing sodium ions includes a sodium-containing phosphate compound having a Nasicon type structure, a sodium-containing phosphate compound having an olivine type structure, and a sodium-containing oxide having a spinel type structure. At least one selected from the group is included. In a preferred embodiment of the solid-state battery of the present invention, the positive electrode layer and the negative electrode layer may be made of the same material.

The positive electrode layer and/or the negative electrode layer may contain a conductive material. At least one of metal materials such as silver, palladium, gold, platinum, aluminum, copper and nickel, carbon and the like can be used as the conductive material contained in the positive electrode layer and the negative electrode layer.

Furthermore, the positive electrode layer and/or the negative electrode layer may contain a sintering aid. Sintering aids include at least one selected from the group consisting of lithium oxide, sodium oxide, potassium oxide, boron oxide, silicon oxide, bismuth oxide and phosphorus oxide.

It should be noted that in a preferred embodiment of the solid-state battery of the present invention, the positive electrode layer and the negative electrode layer are made of the same material. In the solid state battery of the present invention, the positive electrode layer and the negative electrode layer may be made of the same material (eg, in such cases, the positive electrode active material and the negative electrode active material may be of the same type).

(solid electrolyte)
A solid electrolyte is a material that can conduct lithium ions. In particular, a solid electrolyte, which constitutes a battery structural unit in a solid battery, forms a layer capable of conducting lithium ions between the positive electrode layer and the negative electrode layer. Note that the solid electrolyte may be provided at least between the positive electrode layer and the negative electrode layer. That is, the solid electrolyte may also exist around the positive electrode layer and/or the negative electrode layer so as to protrude from between the positive electrode layer and the negative electrode layer. A specific solid electrolyte may be, for example, an oxide system, and examples include a lithium-containing phosphate compound having a Nasicon type structure, an oxide having a perovskite structure, an oxide having a garnet type or a garnet-like structure, and an oxide. material glass-ceramics-based lithium ion conductors, and the like. Lithium-containing phosphate compounds having a Nasicon type structure include Li _x _My (PO ₄ ) ₃ (1≤x≤2, 1≤y≤2, M is the group consisting of Ti, Ge, Al, Ga and Zr). at least one selected from). An example of the lithium-containing phosphate compound having a Nasicon-type structure includes Li _1.2 Al _0.2 Ti _1.8 (PO ₄ ) ₃ and the like. An example of an oxide having a perovskite structure is La _0.55 Li _0.35 TiO ₃ or the like. _An example _of an oxide having _a garnet-type or garnet-like structure is _Li7La3Zr2O12 . As the oxide glass-ceramic lithium ion conductor, for example, a phosphate compound (LATP) containing lithium, aluminum and titanium as constituent elements, and a phosphate compound (LAGP) containing lithium, aluminum and germanium as constituent elements can be used. can be done.

Solid electrolytes capable of conducting sodium ions include, for example, sodium-containing phosphate compounds having a Nasicon-type structure, oxides having a perovskite structure, and oxides having a garnet-type or garnet-like structure. NaxMy(PO ₄ ) ₃ (1≦x≦2, 1≦y≦2, M is selected from the group consisting of Ti, Ge, Al, Ga and Zr) as the sodium-containing phosphate compound having a Nasicon-type structure. at least one).

The solid electrolyte may contain a sintering aid. The sintering aid contained in the solid electrolyte may be selected, for example, from materials similar to those of the sintering aid that can be contained in the positive electrode layer and the negative electrode layer.

The thickness of the solid electrolyte layer is not particularly limited, and may be, for example, 1 μm or more and 15 μm or less, particularly 1 μm or more and 5 μm or less.

(Positive collector layer and negative collector layer)
The positive electrode layer and the negative electrode layer may each include a positive current collecting layer and a negative current collecting layer. The positive electrode current collecting layer and the negative electrode current collecting layer may each have the form of a foil, but from the viewpoint of reducing the production cost of the solid battery by co-firing and reducing the internal resistance of the solid battery, etc., the form of the sintered body is preferred. may have. As the positive electrode current collector that constitutes the positive electrode current collecting layer and the negative electrode current collector that constitutes the negative electrode current collecting layer, it is preferable to use materials having high electrical conductivity, such as silver, palladium, gold, platinum, aluminum, and copper. , nickel, etc. may be used. In particular, copper may be used because it hardly reacts with the positive electrode active material, the negative electrode active material, and the solid electrolyte material, and is effective in reducing the internal resistance of the solid battery. When the positive electrode current collecting layer and the negative electrode current collecting layer have the form of a sintered body, they may be composed of a sintered body containing a conductive material and a sintering aid. The conductive material contained in the positive electrode current collecting layer and the negative electrode current collecting layer may be selected from, for example, the same conductive materials that can be contained in the positive electrode layer and the negative electrode layer. The sintering aid contained in the positive electrode current collecting layer and the negative electrode current collecting layer may be selected, for example, from materials similar to those of the sintering aid that can be contained in the positive electrode layer and the negative electrode layer. It should be noted that the positive electrode current collecting layer and the negative electrode current collecting layer are not essential in the solid battery, and a solid battery without such a positive electrode current collecting layer and the negative electrode current collecting layer is also conceivable. In other words, the solid-state battery in the present invention may be a collector-layer-less solid-state battery.

Although the thickness of the positive electrode layer and the negative electrode layer is not particularly limited, for example, each may be independently 2 μm or more and 50 μm or less, particularly 5 μm or more and 30 μm or less.

Solid-state batteries, specifically battery elements, are generally provided with terminals (eg, external electrodes). In particular, the end face electrodes are provided on the side faces of the battery element. More specifically, there are provided a positive electrode side face electrode connected to the positive electrode layer and a negative electrode side face electrode connected to the negative electrode layer. Such edge electrodes may comprise a highly conductive material. Specific materials for the end face electrodes are not particularly limited, but at least one selected from the group consisting of silver, gold, platinum, aluminum, copper, tin and nickel can be mentioned. In addition, terminals called tab leads are provided at the ends of the end face electrodes for taking out the generated electricity to the outside. The material of the tab lead may contain a material with high electrical conductivity, similar to the material of the end face electrodes. A specific material for the tab lead is not particularly limited, but at least one selected from the group consisting of silver, gold, platinum, aluminum, copper, tin and nickel can be mentioned.

(Characteristic part of the solid-state battery of the present invention)
A solid battery to which the exterior material according to one embodiment of the present invention is applied includes a battery element having a positive electrode layer, a negative electrode layer, and a solid electrolyte layer interposed between the positive electrode layer and the negative electrode layer, and a battery element. It may include an exterior covering material and a conducting portion capable of extracting electricity from the battery element to the outside. The exterior material includes a metal layer, a first thermoplastic resin layer located on the first main surface side of the metal layer, and a second thermoplastic resin layer located on the second main surface side of the metal layer. and wherein both the melting point of the first thermoplastic resin layer and the melting point of the second thermoplastic resin layer are higher than 260°C, that is, the exterior material of the present invention described above.

As described in the characteristics of the exterior material, the exterior material according to one embodiment of the present invention can suppress permeation of water vapor into the exterior material itself. As a result, in the case where an exterior material that suppresses the permeation of water vapor is provided so as to cover the periphery of the solid-state battery, it is possible to suppress the permeation of water vapor into the solid-state battery.

In addition, in one embodiment of the present invention, two thermoplastic resin layers and an adherend such as a metal layer positioned between them can be bonded to each other without necessarily using an adhesive layer. It is also possible to reduce the overall thickness of the material. That is, in the case where the exterior material is integrated with the solid-state battery, it can contribute to the reduction of the size of the integrated product itself. By reducing the size of the integrated body itself, it is possible to contribute to space saving and the like.

In addition, in one embodiment of the present invention, since the adhesive layer is not necessarily used, the step of applying the adhesive layer and the step of curing the adhesive layer can be omitted. Therefore, the solid-state battery of one embodiment of the present invention can be a low-cost solid-state battery.

The form in which the exterior material covers the solid battery is not particularly limited, and conventional forms can be adopted. Regardless of the form, the solid battery obtained by integrating the exterior material and the battery element can exhibit the above effects of the present invention. The form in which the exterior material of the present invention covers the battery element can adopt, for example, the following embodiments.

The first embodiment, as shown in FIGS. 3 and 4, is an embodiment in which the exterior material is composed of a continuous single structure, and the exterior material of the single structure surrounds the battery element. In the second embodiment, as shown in FIGS. 5 to 12, the exterior material is an exterior composite composed of a first exterior material and a second exterior material, and the exterior composite surrounds the battery element. It is an embodiment.

<First Embodiment>
FIG. 3 is a cross-sectional view schematically showing a solid-state battery according to one embodiment of the invention. FIG. 4 is a cross-sectional view schematically showing a solid-state battery according to one embodiment of the invention.

From the viewpoint of surface-mounting solid-state batteries, for example, an embodiment as shown in FIG. 3 may be adopted. FIG. 3 shows a solid state battery 200 comprising a battery element 100 covered by a single sheathing material 11 and having a conducting part 20 consisting of an end face electrode 21 and a tab lead 22. FIG. The end surface electrode 21 is connected to one end of the tab lead 22, and the other end of the tab lead 22 is exposed to the outside. The solid state battery 200 of FIG. 3 is surface mountable to a substrate through the exposed tab lead 22 ends.

In one aspect, as shown in FIG. 4 , the conductive portion 20 (tab lead 22 ) may be drawn out and the tab lead 22 of the drawn conductive portion 20 may be provided along the contour surface of the battery element 100 . In other words, the tab leads 22 of the conducting portion 20 and the outer covering 11 may be provided along the contour surface of the battery element 100 .

In this specification, the "contour surface of the battery element 100" means a surface that forms the shape or appearance of the battery element 100. In this specification, “the tab leads 22 of the conductive portion 20 and the exterior material 11 are provided along the contour surface of the battery element 100 ” means that the tab lead 22 of the conductive portion 20 and the exterior material 11 are provided along the outline of the battery element 100 . It means a state of being provided substantially parallel to the extending direction of the surface.

In other words, the tab leads 22 of the conductive portion 20 and the exterior material 11 may extend in substantially the same direction as the extending direction of the contour surface of the battery element 100 . In this specification, the term “extending direction of the contoured surface of the battery element 100” means the direction in which the contoured surface extends in the longitudinal direction. The conductive portion 20 and the exterior material 11 may at least at first glance extend in substantially the same direction as the extending direction of the contour surface of the battery element 100 . It does not necessarily need to extend completely in the same direction as the extending direction of . For example, due to the positional relationship among each of the conducting portion 20, the exterior material 11, and the battery element 100, a portion of the conducting portion 20 and a portion of the exterior material 11 extend substantially in the same direction as the outline surface of the battery element 100. There may be portions that do not extend in parallel.

By forming the tab leads 22 of the conducting part 20 along the outline of the battery element 100, the conducting part 20 of the solid battery 200 shown in FIG. 4 can have a large contact area with the substrate in surface mounting. When the contact area between the conductive portion 20 and the substrate is large, the solid-state battery 200 can be more firmly surface-mounted on the substrate.

In one aspect, the lead-out portion (corresponding to the tab lead 22) of the conducting portion 20 to the outside may include the bent portion 20A. The bent portion here means a bent portion. There is no particular limitation on the form of bending. For example, as shown in FIG. 4, in a form in which the conductive part 20 is composed of an end surface electrode 21 and a tab lead 22, the portion leading to the outside of the conductive part 20 has a right-angled portion. It means a bent part even if it is Alternatively, the lead-out portion of the conducting portion 20 to the outside may be bent so as to have an arc (curved) portion.

A portion (corresponding to the tab lead 22) of the conductive portion 20 that is led out to the outside is connected to an electronic substrate or the like when the solid-state battery 200 according to one embodiment of the present invention is surface-mounted. At that time, depending on the mounting area of the solid battery 200 according to one embodiment of the present invention, the positional relationship between the solid battery 200 and the electronic base material, etc., and the connection method between the solid battery 200 and the electronic base material, etc. A part drawn out to the outside (corresponding to the tab lead 22) can be bent.

The length of the conducting portion 20 drawn out to the outside is not particularly limited as long as electricity can be extracted from the conducting portion 20 . The conductive portion 20 (specifically, the tab lead 22) along the contour of the battery element 100 may have its end portion provided on the upper surface side or the lower surface side of the solid battery 200, for example, the lower surface side. As a result, the solid-state batteries 200 can be mounted in parallel on the electronic substrate, and the overall surface mounting area can be further reduced. In addition, from the viewpoint of further reducing the overall surface mounting area and achieving more reliable surface mounting of the solid battery 200, at least a part of the lead-out portion of the conductive portion 20 is "flat" with the surface of the electronic substrate. may come into contact. The contact area between the conducting part 20 and the electronic substrate can be increased by making contact with the "surface". As shown in FIG. 4, such a form is provided with a bent portion in the lead portion of the conductive portion 20 so that at least a portion of the lead portion of the conductive portion 20 to the outside is substantially parallel to the surface of the electronic substrate. achievable.

It should be noted that the end of the conductive portion 20 drawn out does not necessarily have to be fixed to the exterior material 11, and the end may be a free end that can be freely moved. In this respect, from the viewpoint of reducing the mounting area, in one aspect, at least the end of the conductive portion 20 drawn out may be fixed to the exterior material 11 .

By adopting such a form, the end of the conductive portion 20 drawn out is brought into close contact along the side surface of the battery element 100, and the close contact state can be maintained.

Furthermore, by maintaining the close contact state, when an external force acts on the pulled-out end of the conducting portion 20, the pulled-out end of the conducting portion 20 is preferably bent and deformed. can be prevented. As a result, the solid-state battery 200 can be appropriately surface-mounted on the electronic substrate.

The method of fixing the drawn-out end of the conductive part 20 to the exterior material 11 is not particularly limited. For example, the drawn-out end portion of the conductive portion 20 may be fixed to the exterior material 11 by thermal fusion. For example, the drawn-out end of the conducting portion 20 may be fixed to the exterior material 11 using an adhesive. The form of the adhesive is, for example, liquid, paste, sheet, solid, and powder. Types of adhesives include, for example, water-based adhesives, chemical reaction adhesives, solvent-based adhesives, and hot-melt adhesives. The adhesive is not particularly limited as long as the adhesive strength of the adhesive does not change before and after the reflow process. For example, the material of the adhesive can be at least one selected from the group consisting of silicone-based resins, acrylic-based resins, epoxy-based resins, urethane-based resins, and the like.

During charging and discharging of the solid battery 200, the active material contained in each electrode layer expands along the stacking direction as ions move in the solid electrolyte layer between the positive electrode layer and the negative electrode layer. , can shrink. In particular, when the active material, that is, the electrode layer expands along the stacking direction, this causes upward acting tensile stress and downward acting tensile stress. In this regard, according to this aspect, when the solid-state battery 200 is surface-mounted on the electronic substrate, a minute space can be provided between the solid-state battery 200 and the electronic substrate. Due to the presence of such a space, it is also possible to accommodate the portion of the solid-state battery 200 that expands due to the expansion of the electrode layers along the stacking direction.

The exterior material 11 may be fixed to the end face electrode 21 by thermal fusion. Specifically, the first thermoplastic resin layer 11 a or the second heat-sealable resin layer 11 c of the exterior material 11 may be heat-sealed to the end surface electrode 21 . In this case, the difference between the melting point of the first thermoplastic resin layer 11a and the melting point of the second thermoplastic resin layer 11c may be 20° C. or more. In this embodiment, the melting point of the second thermoplastic resin layer 11c may be lower than the melting point of the first thermoplastic resin layer 11a. By adopting such a form, it becomes easy to heat-seal only the second thermoplastic resin layer 11 c having a relatively low melting point to the end surface electrode 21 .

<Second embodiment>
From the viewpoint of surface-mounting a solid-state battery, for example, an embodiment as shown in FIG. 5 may be adopted. Specifically, the solid-state battery shown in FIG.
A cladding composite is provided of two or more claddings, the two or more claddings including a first cladding and a second cladding, the first cladding and the second cladding being interconnected. forming an overlapping region that overlaps with
A conductive portion is drawn out from the overlapping region to the outside.

FIG. 5 is a cross-sectional view schematically showing a solid-state battery according to one embodiment of the invention. FIG. 6 is a cross-sectional view schematically showing how the solid-state battery according to one embodiment of the present invention prevents water vapor intrusion. FIG. 7 is a cross-sectional view schematically showing a solid-state battery according to one embodiment of the invention. FIG. 8 is a perspective view schematically showing a solid-state battery according to one embodiment of the invention. FIG. 9 is a cross-sectional view schematically showing a solid-state battery (expanded state) according to one embodiment of the present invention. FIG. 10 is a cross-sectional view schematically showing a solid-state battery according to one embodiment (with sealant) of the present invention. FIG. 11 is a cross-sectional view schematically showing a solid-state battery according to another embodiment of the invention. FIG. 12 is a cross-sectional view schematically showing a solid-state battery according to another embodiment of the invention.

As used herein, the term "exterior composite" refers to a structure (structure) in which two or more exterior materials are assembled or combined, and can also be referred to as an exterior assembly. As used herein, "composite" refers to a state in which two or more things come together to become one. The term “conducting portion” as used in this specification is a general term for members that contribute to electricity extraction, such as the end face electrodes 21 provided on the battery element 100 and the tab leads 22 connected to the end face electrodes 21 . In other words, the conducting portion 20 has the end face electrode 21 provided on the battery element 100 and the tab lead 22 connected to the end face electrode 21 .

That is, in one embodiment of the present invention, the battery element 100 is covered with the exterior composite 10 configured by combining two or more exterior materials. In other words, the sheathing composite 10 surrounds the battery element 100 . As an example, as shown in FIG. 5, an exterior composite 10 is composed of a first exterior material 11 and a second exterior material 12 . Furthermore, in one embodiment of the present invention, the exterior composite 10 is formed with an overlapping region 50 in which the first exterior material 11 and the second exterior material 12 overlap each other, and the exterior from the overlap region 50 is formed. The conducting portion 20 is pulled out to the .

The first exterior material 11 has a metal layer 11b, a first thermoplastic resin layer 11a, and a second thermoplastic resin layer 11c. The second exterior material 12 has a metal layer 12b, a first thermoplastic resin layer 12a, and a second thermoplastic resin layer 12c. Each layer constituting the first exterior material 11 and each layer constituting the second exterior material 12 may be the same.

Note that the positional relationship between the first exterior material 11 and the second exterior material 12 in the overlap region 50 is not particularly limited. Alternatively, the first exterior material 11 may be positioned outside the second exterior material 12 . In other words, in the overlap region 50 , the first sheathing material 11 is provided on the side relatively proximal to the battery element 100 , and the second sheathing material is provided on the side relatively distal to the battery element 100 . Material 12 may be provided. Alternatively, in the overlap region 50 , the second sheathing material 12 is provided on the side relatively proximal to the battery element 100 and the first sheathing material is provided on the side relatively distal to the battery element 100 . 11 may be provided. Overlap region 50 may be composed of more than two claddings. For example, in the form shown in FIG. 5, the overlapping region 50 is composed of two layers of the first exterior material 11 and the second exterior material 12, but for example, a third exterior material and a fourth exterior material may also be used. An overlapping region may be configured by

As used herein, the term “overlapping region” broadly refers to a region where the first exterior material 11 and the second exterior material 12 overlap each other, and in a narrow sense, overlaps with a part of the first exterior material 11. It refers to a region where a part of the second exterior material 12 overlaps with each other. "Mutually overlapping" refers to a state in which the main surface of one exterior material and the main surface of the other exterior material directly or adjacently face each other. In other words, even if resin, metal, or the like is interposed between the main surface of one exterior material and the main surface of the other exterior material, it is considered that they "overlap each other" in the above state. The term "steam" as used herein is not particularly limited to gaseous water, but also includes liquid water and the like. In other words, the term "water vapor" is used to broadly encompass items related to water regardless of its physical state. Therefore, "steam" can also be referred to as moisture, etc. In particular, water in a liquid state may include condensed water in which water in a gaseous state is condensed.

As used herein, the term “drawn out” means that at least a part of another independent component located in a component extends from the component to the outside, and the independent other means that at least part of the constituent elements of is exposed to the outside. That is, in this specification, "the conductive portion 20 is pulled out from the overlapping region 50 of the exterior composite 10" means that the battery element 100 covered with the exterior composite 10 can be electrically connected. As shown in FIG. 5, a part of the conductive portion 20 passes through between the first and second

exterior materials

11 and 12 forming the overlap region 50 of the exterior composite body 10 to the outside. and exposed state.

As shown in FIG. 5, the first packaging material 11, which is a component of the packaging composite 10, does not need to cover the entire battery element 100. Similarly, the second packaging material 12 also covers the entire battery element 100. does not need to be covered. Ultimately, the first exterior material 11 and the second exterior material 12 may be arranged so as to cover the entire battery element 100 with the first exterior material 11 and the second exterior material 12 . That is, it is sufficient that the exterior composite 10 is finally arranged so as to cover the entire battery element 100 . Also, as shown in FIG. 5, the overlap region 50 can be formed such that a portion of one facing and a portion of the other facing cover each other. In other words, the overlap region 50 can be formed by stacking a portion of the first sheathing 11 and a portion of the second sheathing 12 on top of each other. The direction in which the first and second exterior materials are stacked in overlapping region 50 is substantially perpendicular to the stacking direction of positive electrode layer 110 , negative electrode layer 120 , and solid electrolyte layer 130 in battery element 100 . Moreover, the direction in which the conductive portion 20 is pulled out from the overlap region 50 is substantially perpendicular to the direction in which the first and second exterior materials are stacked in the overlap region 50, while the battery element 100 is It is substantially parallel to the stacking direction of the positive electrode layer 110 , the negative electrode layer 120 , and the solid electrolyte layer 130 . By adopting such a configuration, like the solid-state battery 200 of FIG. 11 can be interposed. In other words, the tab lead 22 can be connected to the end surface electrode 21 while separating the tab lead 22 and the battery element 100 with the first outer packaging material.

As described above, the solid-state battery 200 according to one embodiment of the present invention adopts a configuration in which the conducting portion 20 is pulled out from the overlapping region 50 of the exterior composite 10 to the outside. With such a configuration, the following technical effects can be achieved.

If water vapor penetrates into the battery element, there is a risk that the battery characteristics will deteriorate. Infiltration of water vapor into such battery elements can be suppressed by covering the periphery of the battery elements with an exterior material as a water vapor permeation prevention layer. In this regard, as shown in FIGS. 16 and 17, in a conventional solid-state battery 200', a single exterior member 13' is configured to cover the battery element 100' by one turn in a cross-sectional view. In order to extract electricity from the battery element 100' to the outside, a tab lead 22', which is a component of the conductive portion, can be connected to the battery element 100' across the exterior material 13'. In other words, the tab lead 22' is configured to traverse the exterior material 13' and protrude outward. In such a configuration, since the tab lead 22' crosses the exterior material 13', a minute gap is generated between the tab lead 22' and the exterior material 13', and the gap is a passage through which water vapor communicates from the outside to the battery element 100'. There is a risk of becoming.

In this regard, in a solid-state battery 200 according to an embodiment of the present invention, as shown in FIGS. 5 and 6, the conductive portion 20 connected to the battery element 100 is pulled out from the overlapping region 50. . Therefore, compared to the conventional solid-state battery 200' covered with a single exterior material 13' (that is, no overlapping region), the outside of the battery in the extending direction (longitudinal direction) of the overlapping region 50 in cross-sectional view is to the battery element 100 can be increased by the length of the overlapping region 50 . As a result, compared with the conventional solid-state battery 200', water vapor 40 can be favorably suppressed from reaching the battery element 100 from the outside.

Also, as can be seen from the above description, the overlapping region 50 is in a state in which one exterior material and the other exterior material overlap each other. That is, the overlapping region 50 is a region composed of two or more layers of exterior materials. Therefore, the thickness of the overlapping region 50 is thicker than the thickness of the exterior composite 10 in the portions other than the overlapping region 50 . As a result, in the thickness direction (transverse direction) of the overlapping region 50 in a cross-sectional view, the overlapping region 50 The thickness of the exterior material in can be increased. Therefore, compared with the conventional solid-state battery 200', it is possible to favorably suppress the water vapor 40 from reaching the battery element 100 from the outside.

If these exterior materials easily permeate water vapor (moisture, gas (carbon dioxide), etc.), water vapor penetrates into the interior of the battery element, and the positive electrode layer, the negative electrode layer, and the solid electrolyte layer adsorb and absorb the water vapor, thereby Battery performance may deteriorate. In view of this point, the water vapor transmission rate in the thickness direction of the exterior material is, for example, less than 5.0×10 ⁻³ g/(m ² day), preferably 0 or more and 5.0×10 ⁻³ g/( m ² · day). The term "water vapor transmission rate" as used herein refers to the transmission rate obtained by the MA method using a gas transmission rate measuring device of model WG-15S manufactured by MORESCO under the measurement conditions of 85°C and 85% RH. pointing to

Alternatively, using a GTms-1 gas permeability measuring device manufactured by Advance Riko Co., Ltd., the measurement conditions are 40° C., 90% RH, and a differential pressure of 1 atm. The water vapor permeability value obtained is 1.0. It may be less than ×10 ⁻³ g/(m ² ·day).

As shown in FIG. 5, the exterior composite 10 has an overlap region 50 formed by overlapping the first exterior material 11 and the second exterior material 12 with each other. In one embodiment of the present invention, overlap region 50 may be achieved by providing second cladding 12 over first cladding 11, as shown in FIG. In that case, with the position of the battery element 100 as a reference, the first packaging material 11 in the overlap region 50 is positioned relatively inside, and the second packaging material 12 in the overlap region 50 is positioned relatively outside. become. In the positioning of the first exterior material 11 and the second exterior material 12, the first thermoplastic resin layer 11a or the second thermoplastic resin layer 11c of the first exterior material 11 and the second exterior material The twelve first thermoplastic resin layers 12a or the second thermoplastic resin layers 12c face each other.

In addition, the term "facing" here means that the layers face each other. For example, as shown in FIG. and the second thermoplastic resin layer 12c of the second exterior material 12 face each other.

In the present invention, the first thermoplastic resin layer 11a or the second thermoplastic resin layer 11c of the first exterior material 11 in the overlap region 50 and the first thermoplastic resin layer 12a or the second thermoplastic resin layer 12a of the second exterior material 12 The following pattern is mentioned as the facing aspect which the 2nd thermoplastic resin layer 12c faces.
(Opposing mode 1)
The first thermoplastic resin layer 11a of the first exterior material 11 and the first thermoplastic resin layer 12a of the second exterior material 12 face each other.
(Opposing mode 2)
The second thermoplastic resin layer 11c of the first exterior material 11 and the second thermoplastic resin layer 12c of the second exterior material 12 face each other.
(Opposing mode 3)
The first thermoplastic resin layer 11a of the first exterior material 11 and the second thermoplastic resin layer 12c of the second exterior material 12 face each other.
(Opposing mode 4)
The second thermoplastic resin layer 11c of the first exterior material 11 and the first thermoplastic resin layer 12a of the second exterior material 12 face each other.
Among the above facing modes 1 to 4, from the viewpoint of facilitating temperature control during heat sealing and/or from the viewpoint of facilitating heat sealing between thermoplastic resins, the solid battery of the present invention is the facing mode 1 and It is good also as the facing aspect 2. FIG.

Among the first thermoplastic resin layer and the second thermoplastic resin layer of each of the first exterior material 11 and the second exterior material 12, the thermoplastic resin layers having a relatively low melting point overlap in the overlapping region 50. They are preferably facing each other. For example, it is preferable that thermoplastic resin layers with relatively low melting points are in contact with each other in the overlap region 50 . By adopting such a configuration, when the overlapping region 50 is heated using an external heat source, only the relatively low melting point thermoplastic resin layers facing each other can be softened and heat-sealed. A thermoplastic resin layer having a relatively high melting point that is not exposed (that is, on the outermost side) is not softened and can maintain its shape. As a result, the shape of the solid battery 200 as a whole can be maintained while heat-sealing the portions where the first exterior material 11 and the second exterior material 12 face each other in the overlapping region 50 . In the first exterior material 11, the difference between the melting point of the first thermoplastic resin layer 11a and the melting point of the second thermoplastic resin layer 11c may be 20° C. or more. In the second exterior material 12, it is preferable that the difference between the melting point of the first thermoplastic resin layer 12a and the melting point of the second thermoplastic resin layer 12c is 20° C. or more. By adopting such a mode, it becomes easier to heat-seal one resin layer to another. Further, in the case of the above aspect, in the first exterior material 11, the melting point of the second thermoplastic resin layer 11c may be lower than the melting point of the first thermoplastic resin layer 11a. In the second exterior material 12, the melting point of the second thermoplastic resin layer 11c may be lower than the melting point of the first thermoplastic resin layer 11a.

The melting point of the thermoplastic resin layer with a relatively low melting point is preferably 20°C or more lower than the melting point of the thermoplastic resin layer with a relatively high melting point. By adopting such a form, only the opposing thermoplastic resin layers having a relatively low melting point are easily heat-sealed to each other.

From the viewpoint of facilitating heat-sealing, the melting point of the thermoplastic resin layer with a relatively low melting point is preferably 40° C. or higher, more preferably 60° C., higher than the melting point of the thermoplastic resin layer with a relatively high melting point. °C or lower. On the other hand, from the viewpoint of facilitating temperature control during heat lamination in the manufacture of exterior materials, the melting point of the thermoplastic resin layer with a relatively low melting point is lower than the melting point of the thermoplastic resin layer with a relatively high melting point. , 120° C. or less, preferably 100° C. or less, more preferably 90° C. or less. The "relatively low melting point thermoplastic resin layer" may be the "second thermoplastic resin layer", and the "relatively high melting point thermoplastic resin layer" may be the "first thermoplastic resin layer." ' may be.

Since the thermoplastic resin of the exterior material according to one embodiment of the present invention itself has adhesiveness, it is not always necessary to provide the sealant on the conducting portion 20 located in the overlapping region 50 . That is, the first thermoplastic resin layer 11a of the first exterior material 11 is directly bonded to one main surface of the conductive portion 20, and the first thermoplastic resin layer 12a of the second exterior material 12 is conductive. It may be directly joined to the other main surface of the portion 20 . That is, it is possible to adopt a form without sealant. Alternatively, the second thermoplastic resin layer 11c of the first exterior material 11 is directly bonded to one main surface of the conductive portion 20, and the second thermoplastic resin layer 12c of the second exterior material 12 is conductive. It may be directly joined to the other main surface of the portion 20 . By adopting such a form, water vapor can be prevented from entering the solid-state battery 200 through the sealant. Moreover, since no sealant is used, the thickness of the exterior composite 10 in the overlapping region 50 can be reduced, which contributes to the reduction in the size of the solid-state battery 200 .

When the sealant is provided on the conducting portion 20 positioned in the overlapping region 50, the sealant 24 may be provided on the conducting portion 20 positioned in the overlapping region 50 as shown in FIG.

Due to the presence of the sealant 24 , the conducting portion 20 positioned in the overlapping area 50 and the two

exterior materials

11 and 12 forming the overlapping area 50 can be adhered. As a result, in the overlapping region 50, the conducting portion 20 and the two

exterior materials

11 and 12 can be surface-bonded in a cross-sectional view, and the shape of the solid-state battery 200 can be more easily maintained.

The sealant 24 is not particularly limited as long as the adhesive strength of the sealant does not change before and after the reflow process. For example, sealant 24 may comprise a resin having a melting point higher than the peak temperature during lead-free solder reflow.

A solid-state battery according to an embodiment of the present invention may further adopt the following aspects.

In one aspect, the conductive portion 20 may be provided so as to be sandwiched between the first exterior material 11 and the second exterior material 12 that constitute the exterior composite 10 (see FIGS. 5 to 8, etc. ). Specifically, the first exterior material 11 is in contact with the conductive portion 20, the second exterior material 12 is in contact with the conductive portion 20, and in that state, the conductive portion 20 is in contact with the first exterior material. It is sandwiched between 11 and the second exterior material 12 . Alternatively, as shown in FIG. 5, a conducting portion 20 may be provided between the outer surface of the first exterior material 11 and the inner surface of the second exterior material 12 . In such a configuration, the conductive portion 20 is sandwiched between the first exterior material 11 and the second exterior material 12 so as to be substantially parallel to the first exterior material 11 and the second exterior material 12. .

That is, the conducting portion 20 is positioned between the first exterior material 11 and the second exterior material 12, and the conducting portion 20, the first exterior material 11, and the second exterior material 12 are integrated. may be in the form By adopting such a configuration, the exterior materials are positioned on both sides of the conducting portion 20 in a cross-sectional view, so that the conducting portion 20 can be brought into surface contact with the two exterior materials, respectively, and the conducting portion 20 and each exterior material can be brought into contact with each other. A minute gap between them can be suitably reduced. As a result, it is possible to suitably prevent water vapor from passing through the overlapping region 50 .

From the viewpoint of suppressing water vapor from passing through the overlapping region 50 on both the positive electrode side and the negative electrode side, two overlapping regions 50 may be provided in a cross-sectional view. Specifically, there may be provided one for sandwiching the conductive portion on the positive electrode side (corresponding to the tab lead 22) and another for sandwiching the conductive portion on the negative electrode side (corresponding to the tab lead 22).

In one aspect, it is preferable that the end face electrodes of the conducting portion 20 and the exterior composite 10 are provided along the contour surface of the battery element 100 (see FIGS. 5 to 12, etc.).

In this specification, the "contour surface of the battery element 100" means a surface that forms the shape or appearance of the battery element 100. In this specification, “the end surface electrode of the conductive portion 20 and the exterior composite 10 are provided along the contour surface of the battery element 100” means that the end surface electrode of the conductive portion 20 and the exterior composite 10 It means a state in which it is provided substantially parallel to the extending direction of the contour surface of the.

In other words, it is preferable that the end surface electrodes of the conducting portion 20 and the exterior composite 10 extend in substantially the same direction as the extending direction of the contour surface of the battery element 100 . In this specification, the term “extending direction of the contoured surface of the battery element 100” means the direction in which the contoured surface extends in the longitudinal direction. The conducting portion 20 and the exterior composite 10 may at least at first glance extend in substantially the same direction as the extending direction of the contour surface of the battery element 100. It does not necessarily have to extend in exactly the same direction as the extension of the contoured surface of element 100 . For example, due to the positional relationship among each of the conductive portion 20, the exterior composite 10, and the battery element 100, a portion of the conductive portion 20 and a portion of the exterior composite 10 are aligned with the extending direction of the contour surface of the battery element 100. There may be portions that do not extend substantially in parallel.

In the conventional solid-state battery 200', as described above, the tab lead 22', which is a constituent element of the conductive portion, is configured to cross the exterior material 13' and protrude outward. Therefore, the area required for mounting in the conventional solid-state battery 200' is further required for the area of the tab leads protruding to the outside. In addition, since this tab lead is a part that extracts electricity from the solid-state battery and does not contribute to the power generation of the solid-state battery, it can lead to a decrease in the power generation capacity per unit area of the solid-state battery depending on the area of the projecting conductive portion.

Regarding this point, in one embodiment of the present invention, the conducting portion 20 is drawn out from the overlapping region 50 where the first covering material 11 and the second covering material 12 overlap each other. Overlapping region 50 is a component of exterior composite 10 that covers battery element 100 , and thus can generally follow the contours of battery element 100 . Therefore, the conductive portion 20 drawn out from the overlapping region 50 can also have a structure in which protrusion along the contour of the battery element 100 is suppressed. Since the conductive part 20 (specifically, the tab lead 22) can be configured along the contour of the battery element 100 instead of the projecting structure, the solid battery 200 according to one embodiment of the present invention as a whole can be surface-mounted on the electronic substrate. can be made

In one aspect, it is preferable that the portion (corresponding to the tab lead 22) of the conductive portion 20 led out to the outside has a bent portion 20A (see FIGS. 6 to 8, etc.). The bent portion here means a bent portion. There is no particular limitation on the shape of the bend, and for example, as shown in FIGS. 6 to 8, the portion of the conductive portion 20 leading to the outside may be bent so as to have a right-angled portion. Alternatively, the lead-out portion of the conducting portion 20 to the outside may be bent so as to have an arc (curved) portion, specifically, it may be bent along the surface of the exterior material. The form in which the tab lead 22 connected to the end face electrode 21 is drawn out is not particularly limited, and for example, as shown in FIG. In other words, the tab lead 22 may be configured to include multiple bends.

As shown in FIG. 6, the portion (corresponding to the tab lead 22) of the conducting portion 20 that is led out to the outside is connected to the electronic substrate 300 or the like when the solid-state battery 200 according to one embodiment of the present invention is surface-mounted. . At that time, depending on the mounting area of the solid battery 200 according to one embodiment of the present invention, the positional relationship between the solid battery 200 and the electronic substrate 300, etc., the connection method between the solid battery 200 and the electronic substrate 300, etc., the conductive part A portion (corresponding to tab lead 22) of lead 20 to the outside can be bent.

The length of the conducting portion 20 drawn out to the outside is not particularly limited as long as electricity can be extracted from the conducting portion 20 . From the viewpoint of suitable surface mounting of a solid-state battery, the lead-out conductive part 20 is covered with the first packaging material 11 or the second packaging material 12 at the end of the drawn-out conductive part 20 of the battery element 100 . is preferably provided on at least one of the upper surface side and the lower surface side of the . Specifically, the conductive portion 20 (specifically, the tab lead 22 ) along the contour of the battery element 100 is preferably provided with its end portion on the upper surface side or the lower surface side of the solid battery 200 , for example, the lower surface side. As a result, the solid-state batteries 200 can be mounted in parallel on the electronic substrate 300, and the overall surface mounting area can be further reduced. In addition, from the viewpoint of further reducing the overall surface mounting area and achieving more reliable surface mounting of the solid-state battery 200, at least a portion of the lead-out portion of the conductive portion 20 is “planed” with the surface of the electronic base 300. contact is preferred. The contact area between the conductive portion 20 and the electronic substrate 300 can be increased by making contact with the “surface”. In such a form, as shown in FIG. 6, a bent portion is provided in the drawn portion of the conductive portion 20 so that at least a portion of the drawn portion of the conductive portion 20 to the outside is substantially parallel to the surface of the electronic substrate 300. can be achieved with

It should be noted that the end of the conductive portion 20 pulled out does not necessarily need to be fixed to the first exterior material 11 or the second exterior material 12, and the end may be a freely movable free end. In this respect, from the viewpoint of reducing the mounting area, in one aspect, at least the end of the conductive portion 20 drawn out is preferably fixed to the first exterior material 11 or the second exterior material 12 .

By adopting such a form, the end of the conductive portion 20 drawn out is brought into close contact along the side surface of the battery element 100, and the close contact state can be maintained. Since the portion protruding from the solid-state battery can be suppressed more reliably, the mounting area can be reduced.

Furthermore, by maintaining the close contact state, when an external force acts on the pulled-out end of the conducting portion 20, the pulled-out end of the conducting portion 20 is preferably bent and deformed. can be prevented. As a result, the solid-state battery 200 can be appropriately surface-mounted on the electronic substrate 300 .

The method of fixing the drawn-out end of the conducting portion 20 to the first exterior material 11 or the second exterior material 12 is not particularly limited. For example, the drawn-out end portion of the conductive portion 20 may be fixed to the first exterior material 11 or the second exterior material 12 by heat sealing. For example, the drawn-out end of the conductive portion 20 may be fixed to the first exterior material 11 or the second exterior material 12 using an adhesive. The form of the adhesive is, for example, liquid, paste, sheet, solid, or powder. Types of adhesives include, for example, water-based adhesives, chemical reaction adhesives, solvent-based adhesives, and hot-melt adhesives. The adhesive is not particularly limited as long as its adhesive strength does not change before and after the reflow process. For example, the material of the adhesive can be at least one selected from the group consisting of silicone-based resins, acrylic-based resins, epoxy-based resins, urethane-based resins, and the like.

As shown in FIG. 7, the tab leads 22 are connected to the end face electrodes 21, and electricity can be taken out from the battery element 100 via the tab leads 22 to the outside. A method for connecting the tab lead 22 and the edge electrode 21 is not particularly limited as long as the tab lead 22 and the edge electrode 21 are electrically connected. For example, the tab lead 22 and the end face electrode 21 may be connected by conductive paste or by welding.

During charging and discharging of the solid battery 200, the active material contained in each electrode layer expands and contracts along the stacking direction as ions move in the solid electrolyte layer between the positive electrode layer and the negative electrode layer. can. In particular, when the active material, that is, the electrode layer expands along the stacking direction, this causes upward acting tensile stress and downward acting tensile stress. In this respect, according to this aspect, when the solid-state battery 200 is surface-mounted on the electronic substrate 300 , a minute space can be provided between the solid-state battery 200 and the electronic substrate 300 . Due to the presence of such a space, it is also possible to accommodate the expanded portion of the solid-state battery 200 due to the expansion of the electrode layers along the stacking direction (see FIG. 9).

In one aspect, overlapping regions 50 may be provided along the sides of battery element 100 . It may be provided along the entire side surface of the battery element 100 (see FIGS. 6 to 9, etc.). As used herein, the term “side surface” means a surface that extends in a direction relatively perpendicular to the upper surface or the lower surface among the surfaces that constitute the battery element 100 . As can be seen from the above description, there are a plurality of “side surfaces” depending on the form of the battery element 100 . Therefore, in the present invention, "the overlapping region is provided along the side surface of the battery element 100" means that the overlapping region is provided on the surface of the battery other than the upper surface or the lower surface of the battery element 100. means that

By adopting such a configuration, the overlapping area 50 does not protrude from the battery element 100, so the mounting area required for surface mounting is reduced. In particular, when the end portion of the conducting portion 20 (specifically, the tab lead 22) along the contour of the battery element 100 is provided on the upper surface side or the lower surface side of the solid battery 200, for example, the lower surface side, the conducting portion 20 (specifically, The portion other than the end of the tab lead 22) can be accommodated in the overlap region 50 along the side surface of the battery element 100, so that the solid battery 200 can be surface-mounted on the electronic substrate 300 and water vapor can be prevented from entering the battery. and can be suitably compatible.

From the viewpoint of preventing water vapor from entering the battery element 100, the overlapping region 50 may be wide. Specifically, in a cross-sectional view, it is preferable that the length of the overlapping region 50 along the longitudinal direction of the tab lead 22 is longer. The length of the overlap region 50 may be 10% or more, preferably 20% or more, or 30% or more of the height of the battery element 100 (that is, the length from the top surface to the bottom surface of the battery element 100). more preferably 40% or more. In addition, from the viewpoint of facilitating adjustment of the position and length of the conductive portion 20 drawn to the outside, the length of the overlapping region 50 should be 150% or less of the height of the battery element 100, preferably 100% or less, more preferably 80% or less, still more preferably 70% or less, particularly preferably 60% or less. The length of overlap region 50 need not be of uniform length throughout overlap region 50 . For example, overlap regions 50 may have different lengths, as shown in the cross-sectional view of FIG.

In one aspect, the first exterior material 11 and the second exterior material 12 have a metal layer 11b and a metal layer 12b as intermediate layers (see FIG. 7). When the battery element 100 is covered with the first exterior material 11, the metal layer 11b, which is an intermediate layer of the exterior material, is electrically connected to the positive electrode side end surface electrode 21 and the negative electrode side end surface electrode 21, and the metal layer 11b is electrically connected to the end surface electrode 21 of the negative electrode side. An insulating material may be provided on the end face of the exterior material from the viewpoint of preventing a short circuit from occurring. The method of insulation treatment for providing the insulating material is not particularly limited, and any method may be used as long as it contributes to the prevention of short circuiting of the battery element 100 via the exterior material.

The positional relationship between the conductive portion 20 and the overlapping region 50 is not particularly limited until confirmation, and any structure may be employed according to the form of surface mounting. For example, structures as shown in FIGS. 11 and 12 can be adopted. As an example, in the structure of FIG. 11 , the exposed portions of the conductive portions 20 on the positive electrode side and the negative electrode side are positioned to face each other with the battery element 100 interposed therebetween. As a result, the conductive portion 20 on the positive electrode side and the conductive portion 20 on the negative electrode side of the solid-state battery 200 are positioned further apart from each other, so that the possibility of short-circuiting between the two electrodes can be reduced. Further, as shown in FIG. 12, depending on where the solid-state battery 200 is mounted, the design of the overlapping region between the positive electrode side and the negative electrode side and the design of the tab lead 22 can be appropriately changed to be asymmetrical. This enables flexible surface mounting according to the surface configuration of the surface mounting destination of the solid battery 200 .

Also, the thickness of the overlap region 50 is determined by the thicknesses of the first exterior material 11 and the second exterior material 12 forming the overlap region.

The thickness of the overlapping region is preferably 2 μm or more and 1000 μm or less, more preferably 4 μm or more and 600 μm or less, and still more preferably 6 μm or more, from the viewpoint of further suppressing the deterioration of the battery performance due to the penetration of water vapor into the battery element. It may be in the range of 200 μm or less, for example 100 μm.

In the above, the case where the exterior material of the present invention is applied to a solid battery provided with the exterior material of the present invention has been described in detail. Aspects of the various solid state batteries described above are also applicable to other electronic devices, as shown in the embodiments below.

<Third embodiment>
For example, as shown in FIG. 13, the exterior material according to one embodiment of the present invention is a circuit board (or composite module, etc.) provided with a plurality of electronic devices (for example, capacitors, resistors, coils, diodes, transistors, etc.). ) 610. FIG. 13 shows a packaged circuit board 600 in which a circuit board 610 is assembled with a sheath composite 10 consisting of a first sheath 11 and a second sheath 12 . Constructed by covering.

(Manufacturing method of the solid-state battery of the present invention)
A method for manufacturing a solid-state battery according to an embodiment of the present invention will be described below. In the following, as solid-state batteries provided with the exterior material of the present invention, a manufacturing method of a solid-state battery of the first embodiment and a manufacturing method of a solid-state battery of the second embodiment will be described. These production methods are merely examples of the production method of the solid-state battery provided with the exterior material of the present invention, and do not limit the present invention.

First, before describing the manufacturing method of the first embodiment, the manufacturing method of the second embodiment will be described.

Manufacture of a solid-state battery according to an embodiment of the present invention (second embodiment) roughly includes the following steps (i) to (iv) in order (see FIGS. 14(a) to 14(h)): . Specifically, a method for manufacturing a solid-state battery according to an embodiment of the present invention includes:
(i) preparing a battery element 100 comprising a positive electrode layer 110, a negative electrode layer 120, and a solid electrolyte layer 130 interposed between the positive electrode layer 110 and the negative electrode layer 120;
(ii) providing a first exterior material 11 so as to partially cover the battery element 100;
(iii) providing a conductive portion 20 capable of extracting electricity from the battery element 100 to the outside;
(iv) providing the second exterior material 12 so as to cover the rest of the battery element 100 other than a portion thereof;
In particular, in the method for manufacturing a solid-state battery according to an embodiment of the present invention, an overlapping region 50 is formed in which the first exterior material 11 and the second exterior material 12 overlap each other, and A second exterior member 12 is provided so that the conductive portion 20 can be pulled out.
In addition, the first exterior material 11 and the second exterior material 12 are composed of a metal layer, a first thermoplastic resin layer located on the first main surface side of the metal layer, and a second layer of the metal layer. and a second thermoplastic resin layer positioned on the main surface side, wherein both the melting point of the first thermoplastic resin layer and the melting point of the second thermoplastic resin layer are higher than 260°C.

For better understanding of the present invention, one manufacturing method will be illustrated below, but the present invention is not limited to this method. In addition, chronological matters such as the following order of description are merely for the convenience of explanation, and are not necessarily bound by it.

[Preparation of the first exterior material]
First, as shown in FIG. 14(a), the first exterior material 11 of the present invention is prepared. The first exterior material 11 includes a metal layer 11b, a first thermoplastic resin layer 11a located on the first main surface side of the metal layer 11b, and a second resin layer 11a located on the second main surface side of the metal layer 11b. 2 thermoplastic resin layers 11c. The first exterior material 11 may be produced and prepared according to the above (the manufacturing method of the exterior material of the present invention).

[Deep drawing of the first exterior material]
Next, as shown in FIG. 14B, the first exterior material 11 is formed into a shape that covers the battery element 100 by drawing. The drawing process is a processing method in which pressure is applied to the first exterior material 11 to draw it into a concave shape (or a cup shape) so that the first exterior material 11 covers the battery element 100. Especially, if it is a processing method. There are no restrictions. For example, the first packaging material 11 is placed on a box-shaped mold that follows the shape of the battery element 100, and pressure is applied from above the first packaging material 11 with a mold that imitates the shape of the battery element 100. By adding, the first exterior material 11 that covers the battery element 100 is formed. Without being limited to this, the drawing process may be performed by pressing the battery element 100 against the first exterior material 11 .

[Installation of first exterior material 11]
Next, as shown in FIG. 14( c ), the battery element 100 is inserted into the first exterior material 11 obtained by the above method, and the first exterior material 11 is attached to the battery element 100 . Specifically, the first exterior material is covered so that the upper surface or the lower surface of the battery element 100 is partially exposed. In a preferred embodiment, the first exterior material is attached so as to cover surfaces other than the top surface or the bottom surface of the battery element 100 . More specifically, the first exterior material 11 is attached so that the end face of the first exterior material is located on the boundary line between the top surface and the side surface of the battery element 100 . Note that the end face electrodes 21 may be attached in advance to the side faces of the battery element 100 .

An insulating material 31 may be provided on the end face of the first exterior material 11 to prevent the battery element 100 from short-circuiting. The insulating material 31 is not particularly limited as long as it has electrical insulation, and may be, for example, an insulating resin. At least one selected from the group consisting of epoxy-based resins, acrylic-based resins, phenol-based resins, and synthetic rubbers can be used as the material of the insulating resin.

[Attachment of tab lead 22]
Next, as shown in FIGS. 14(d) and 14(e), the tab leads 22 are attached to the end face electrodes 21 provided on the battery element 100 not covered with the first exterior material 11. Next, as shown in FIG. Preferably, a conductive adhesive 23 is applied to the ends of the tab leads 22 by metal mask printing, so that the ends of the tab leads 22 and the end surface electrodes 21 of the battery element 100 are attached so as to be electrically connected to each other. The conductive adhesive 23 may be a conductive paste, and is made of, for example, a resin material containing a conductive filler. Examples of the conductive filler include at least one selected from the group consisting of nickel, copper, aluminum, gold, carbon, etc., and the resin material includes epoxy resin, acrylic resin, silicone resin, and urethane resin. At least one selected from the group consisting of resins and the like can be mentioned.

Next, as shown in FIG. 14(f), with the end of the tab lead 22 connected to the end face electrode 21 of the battery element 100 as a base point, the tab lead 22 is positioned along the outline of the side surface of the battery element 100. The tab lead 22 may be bent when the tab lead 22 is laid across the side of the battery element 100 .

[Installation of second exterior material 12]
Next, the second exterior material 12 is prepared. The second exterior material 12 includes a metal layer 12b, a first thermoplastic resin layer 12a positioned on the first main surface side of the metal layer 12b, and a second resin layer 12a positioned on the second main surface side of the metal layer 12b. 2 thermoplastic resin layers 12c. The second exterior material 12 may be produced and prepared according to the above (the manufacturing method of the exterior material of the present invention). As shown in FIG. 14(g), after positioning the tab lead 22 along the contoured side surface of the battery element 100, the surface side of the battery element 100 not covered with the first exterior material 11 is A second exterior material 12 is placed. After that, the end of the second exterior material 12 is arranged along the side surface of the battery element 100 . At this time, since the end of the first packaging material 11 is already arranged on the side surface of the battery element 100, an overlapping region 50 is formed where the second packaging material 12 and the first packaging material 11 overlap. . Specifically, from the battery element 100 toward the outside, layers are formed in which the battery element 100 , the first packaging material 11 , the tab lead 22 , and the second packaging material 12 are arranged in this order, and the tab lead 22 extends from the overlapping region 50 . It is pulled out. In other words, the conductive portion 20 composed of the end surface electrode 21 and the tab lead 22 is pulled out from the overlapping region.

In addition, in the overlapping region 50, the first exterior material 11 is arranged so that the first thermoplastic resin layer of the first exterior material 11 and the first thermoplastic resin layer of the second exterior material 12 face each other. and the second packaging material 12 are preferably arranged on the battery element 100 . Also, in the overlapping region 50, the facing thermoplastic resin preferably has a relatively low melting point.

From the viewpoint of preventing water vapor from entering the battery element 100, the first exterior material 11 located in the overlap region 50, the tab lead 22 as a component of the conductive portion 20, and the second exterior material 12 are brought into close contact. can be The method of adhesion is not particularly limited, but adhesion can be achieved by heat fusion, mechanical bonding, crimping, welding, adhesives, or the like.
When heat-sealing, for example, in the case of FIG. 14(g) or FIG. 14(h), the overlapping region 50 is heated using an external heat source, and the tab lead 22 is bonded to the first exterior material 11 and the second exterior material. 12 may be heat-sealed. 14(e) or 14(f), the tab lead 22 is heated, and the first exterior material 11 and the second exterior material 12 are adhered to the heated tab lead 22 and heat-sealed. good. In another aspect, the sealant 24 is applied to the tab leads 22 in advance and the sealant 24 is applied to the overlap region 50 from the viewpoint of improving the adhesion between the first exterior material 11 , the tab lead 22 , and the second exterior material 12 . may be provided. For example, the sealant 24 is not particularly limited as long as the adhesive strength of the sealant 24 does not change before and after the reflow process. For example, sealant 24 may comprise a resin having a melting point higher than the peak temperature during reflow. Since the first thermoplastic resin layer 11a and the second thermoplastic resin layer 11c, which constitute the exterior material of the present invention, have improved adhesiveness, they can be bonded to the tab lead 22 without using the sealant 24. It is possible. Moreover, even when the sealant 24 is used, a thinner sealant than before can be used.

[Fixation of tab lead 22]
Finally, as shown in FIG. 14(h), the tab lead 22 with one free end, that is, the end of the tab lead 22 that is not connected to the battery element 100 (that is, the end of the conductive portion 20 drawn out) ) are positioned along the contour surface of the battery element 100 . Specifically, the tab lead 22 is bent so as to be in contact with the first exterior material 11 . At this time, the first packaging material 11 may be heat-sealed to the tab lead 22 by heating the portion where the tab lead 22 and the first packaging material 11 are in contact with each other. Alternatively, an adhesive or the like may be applied to a portion where the tab lead 22 and the first exterior material 11 are in contact, and the tab lead 22 and the first exterior material 11 may be bonded and fixed. The adhesive is not particularly limited as long as the adhesive strength of the sealant 24 does not change before and after the reflow process.

Through these steps, a solid-state battery 200 according to one embodiment of the present invention can be finally obtained (FIG. 14(h)). It should be noted that the bending of the tab lead 22 and the bonding and fixing to the first exterior material in the above [fixing the tab lead 22] may be performed, for example, immediately before the solid battery 200 of the present invention is surface-mounted on the electronic substrate 300. . Specifically, after manufacturing until the state shown in FIG. 14(g) is obtained, the manufacturing may be temporarily stopped before the tab lead 22 is fixed, and temporarily stored in the state shown in FIG. 14(g). Depending on the shape of the electronic base material to be surface-mounted after that, design items such as the presence or absence of bending of the tab lead 22, the length of the part where the tab lead 22 is pulled out, the adhesive fixing position of the tab lead 22, the bending point and the bending direction, etc. You can decide accordingly. By adopting such a process, the solid-state battery 200 of the present invention can be surface-mounted flexibly according to the shape of the electronic substrate.

The finally obtained solid battery 200 according to one embodiment of the present invention can exhibit the following effects.

Specifically, in the obtained solid-state battery 200 according to one embodiment of the present invention, the conducting portion 20 connected to the battery element 100 is pulled out from the overlap region 50 to the outside. Therefore, compared to the conventional solid-state battery 200' covered with a single exterior material 13' (that is, no overlapping region), the outside of the battery in the extending direction (longitudinal direction) of the overlapping region 50 in cross-sectional view is to the battery element 100 can be increased by the length of the overlapping region 50 . As a result, compared with the conventional solid-state battery 200', water vapor 40 can be favorably suppressed from reaching the battery element 100 from the outside.

Also, as can be seen from the above description, the overlapping region 50 is in a state in which one exterior material and the other exterior material overlap each other. That is, the overlapping region 50 is a region composed of two or more layers of exterior material. Therefore, the thickness of the overlapping region 50 is thicker than the thickness of the exterior composite 10 in the portions other than the overlapping region 50 . As a result, in the thickness direction (transverse direction) of the overlapping region 50 in a cross-sectional view, the overlapping region 50 The thickness of the exterior material in can be increased. Therefore, compared with the conventional solid-state battery 200', it is possible to favorably suppress the water vapor 40 from reaching the battery element 100 from the outside.

Further, a method for manufacturing a solid-state battery according to one embodiment of the present invention (first embodiment) roughly includes the following steps (i) to (iv) in order (FIGS. 14(a) to 14(h). )reference). Specifically, a method for manufacturing a solid-state battery according to an embodiment of the present invention includes:
(i) preparing a battery element 100 comprising a positive electrode layer 110, a negative electrode layer 120, and a solid electrolyte layer 130 interposed between the positive electrode layer 110 and the negative electrode layer 120;
(ii) a step of providing an end surface electrode 21 capable of extracting electricity from the battery element 100 to the outside;
(iii) providing the exterior material 11 so as to partially cover the battery element 100;
The exterior material 11 includes a metal layer 11b, a first thermoplastic resin layer 11a positioned on the first main surface side of the metal layer 11b, and a second thermoplastic resin layer 11a positioned on the second main surface side of the metal layer 11b. The melting point of the first thermoplastic resin layer 11a and the melting point of the second thermoplastic resin layer 11c are both higher than 260.degree.

First, the exterior material 11 is prepared as described in [Preparation of the first exterior material] in <Second embodiment> above (Fig. 14a). Next, as described in [Deep drawing of exterior material 11] in <Second embodiment>, exterior material 11 is processed into a concave shape (or cup shape) (Fig. 14b). Next, the battery element 100 having the end face electrodes 21 is inserted into the recessed first packaging material 11, and the packaging material 11 is attached to the battery element 100 (FIG. 14c).

Attach the tab lead 22 to the end face electrode 21 . Next, the exterior material 11 is attached so as to cover the battery element 100 to which the recessed exterior material 11 is attached (on the portion of the remaining battery element 100 not covered by the recessed exterior material 11). At this time, the exterior material 11 is attached so that the tab leads 22 attached to the end face electrodes 21 are exposed to the outside. Through the above steps, the solid battery of the first embodiment is obtained.

Although one embodiment of the present invention has been described above, it is merely a typical example within the scope of application of the present invention. Therefore, those skilled in the art will easily understand that the present invention is not limited to this and that various modifications can be made.

Table 1 shows the configurations of the exterior materials of Examples 1 to 5 and Comparative Example 1 and the evaluation results of the solid-state batteries provided with these exterior materials.

<Example 1>
(Preparation of first exterior material)
A first exterior material was produced as follows.
First, using a heat lamination method, a highly heat-resistant polyamide with a melting point of (305°C) is heat-sealed to one side of an aluminum foil at a temperature of (290)°C to produce an integrated product of the aluminum foil and the highly heat-resistant polyamide. bottom. Next, polyethylene naphthalate having a melting point of (269° C.) was heat-sealed to the other surface of the aluminum foil of the integrated product at a temperature of (255° C.) to produce a first exterior material.

(Production of the second exterior material)
The second exterior material was produced in the same manner as the first exterior material.

(Preparation of battery elements)
A battery element having a positive electrode layer, a negative electrode layer, and a solid electrolyte layer interposed between the positive electrode layer and the negative electrode layer was prepared, and an end face electrode capable of extracting electricity from the battery element to the outside was provided.

(Molding of exterior material)
Drawing processing was performed on the first exterior material and the second exterior material, and the first exterior material and the second exterior material were formed into a cup-like shape. In molding, the inner side of the cup-shaped second exterior material is a relatively low-melting thermoplastic resin layer so that the outer side of the cup-shaped first exterior material becomes a relatively low-melting thermoplastic resin layer. It was molded to become As a result, the thermoplastic resin layers with relatively low melting points are made to face each other in the overlapping region to be formed later.

A cup-shaped first exterior material was attached to the battery body provided with the end face electrodes. Next, a tab lead was attached to the end surface electrode exposed to the outside on the side not covered with the first packaging material 11 . The tab leads attached to the end face electrodes were positioned so as to follow the outline of the side face of the battery element. Next, a second cup-shaped exterior member was attached so as to cover the surface of the battery element that was not covered with the first cup-shaped exterior member. As a result, an overlapping region was formed on the side surface of the battery element where the second exterior material and the first exterior material were overlapped. The overlapping region was heated to heat-seal and seal the first exterior material and the second exterior material in the overlapping region. As described above, a solid battery covered with an exterior material was obtained.

<Examples 2 to 5>
Examples 2 to 5 were obtained in the same manner as in Example 1, except that the thermoplastic resin layers described in Examples 2 to 5 in Table 1 were used.

<Comparative Example 1>
Comparative Example 1 was obtained in the same manner as in Example 1, except that the thermoplastic resin layer described in Comparative Example 1 in Table 1 was used.

<Surface mounting evaluation>
A solid-state battery covered with an exterior material was mounted on a circuit board (FR4) using solder paste. Surface mountability was evaluated based on JIS C60068-2-58. Table 1 shows the evaluation results.

<Evaluation of deterioration of battery elements due to water vapor>
After mounting the solid battery covered with the exterior material on a circuit board (FR4) using solder paste, the characteristics were evaluated under high temperature and high humidity conditions of 60°C and 90% RH and 60°C and 50% RH. . Table 1 shows the evaluation results.

From the above results, it was confirmed that the solid-state battery provided with the exterior material of the present invention could be surface-mounted, and the battery element was not deteriorated by water vapor.

The exterior material according to one embodiment of the present invention can be used for various electronic devices that require water vapor barrier properties. Although merely an example, the exterior material according to one embodiment of the present invention can be used for batteries (primary batteries, secondary batteries, particularly solid batteries), circuit boards, composite modules, electronic components, and the like. A solid-state battery according to an embodiment of the present invention can be used in various fields in which battery use or power storage is assumed. Also, the electronic device according to one embodiment of the present invention can be used in various fields requiring electrical control. Although it is merely an example, the solid-state battery according to one embodiment of the present invention can be used in the electric, information, and communication fields where mobile devices and the like are used (for example, mobile phones, smartphones, smart watches, laptop computers and digital cameras, activities Weighing scales, arm computers, mobile devices such as electronic paper), household and small industrial applications (e.g. electric tools, golf carts, household, nursing care and industrial robots), large industrial applications (e.g. forklifts, elevators, harbor cranes), transportation systems (e.g. hybrid vehicles, electric vehicles, buses, trains, electrically assisted bicycles, electric motorcycles, etc.), power system applications (e.g. various power generation, load conditioners, smart grids , general household installation type storage system, etc.), medical use (medical device field such as earphone hearing aid), medical use (field of medication management system, etc.), IoT field, space / deep sea use (for example, space exploration ), etc.).

10: Exterior Composite 11, 11': Exterior Material,

First Exterior Material

11a, 11a': First

Thermoplastic Resin Layer

11b, 11b':

Metal Layer

11c, 11c': Second Thermoplastic Resin Layer 11d '(11e'): Adhesive layer 12: Second exterior material 12a: First thermoplastic resin layer 12b: Metal layer 12c: Second thermoplastic resin layer 13': Single exterior material 20: Conducting part 20A: bent portion 21: end face electrode 22, 22': tab lead 23: conductive adhesive 24: sealant 31: insulating material 40: water vapor 50: overlapping region 100, 100': battery element 110: positive electrode layer 120: negative electrode layer 130 : solid electrolyte layer 200, 200': solid battery 300: electronic base material 310: electronic base material connecting portion 401: first heating roll 402: second heating roll 501: first cooling roll 502: second cooling roll 511a: second 1 thermoplastic resin material 511b: metal layer 511c: second thermoplastic resin material 600: packaged circuit board 610: circuit board

Claims

A metal layer, a first thermoplastic resin layer located on the first main surface side of the metal layer, and a second thermoplastic resin layer located on the second main surface side of the metal layer,
The exterior material, wherein both the melting point of the first thermoplastic resin layer and the melting point of the second thermoplastic resin layer are higher than 260°C.
The exterior material according to claim 1, wherein at least one of the first thermoplastic resin layer and the second thermoplastic resin layer is directly bonded to the metal layer.
The exterior material according to claim 1 or 2, wherein the difference between the melting point of the first thermoplastic resin layer and the melting point of the second thermoplastic resin layer is 20°C or more.
A group in which the first thermoplastic resin layer and the second thermoplastic resin layer are composed of liquid crystal polymer, polyethylene naphthalate, aromatic polyetherketone resin, fluorine resin, polyamide resin, and polyphenylene sulfide resin. The exterior material according to any one of claims 1 to 3, which is composed of at least one thermoplastic resin selected from the above.
The exterior material according to any one of claims 1 to 4, wherein the first thermoplastic resin layer and the second thermoplastic resin layer are made of the same type of thermoplastic resin.
A battery element comprising a positive electrode layer, a negative electrode layer, and a solid electrolyte layer interposed between the positive electrode layer and the negative electrode layer; an exterior material covering the battery element; a conducting portion;
The exterior material comprises a metal layer, a first thermoplastic resin layer located on the first main surface side of the metal layer, and a second thermoplastic resin layer located on the second main surface side of the metal layer. a layer and
A solid-state battery, wherein the melting point of the first thermoplastic resin layer and the melting point of the second thermoplastic resin layer are both higher than 260°C, which is an exterior material.
The solid-state battery according to claim 6, wherein the difference between the melting point of the first thermoplastic resin layer and the melting point of the second thermoplastic resin layer is 20°C or more.
The solid state battery according to claim 6 or 7, wherein the second thermoplastic resin layer has a lower melting point than the first thermoplastic resin layer.
A sheathing composite is provided comprising two or more of said sheathing materials, said two or more said sheathing materials comprising a first said sheathing material and a second said sheathing material, said first said sheathing material and forming an overlapping region where the second exterior material overlaps with each other;
The solid state battery according to any one of claims 6 to 8, wherein said conductive portion is drawn out from said overlapping region to said outside.
With respect to the position of the battery element, the first exterior material is positioned relatively inside and the second exterior material is positioned relatively outside in the overlap region,
The first thermoplastic resin layer or the second thermoplastic resin layer of the first exterior material, and the first thermoplastic resin layer or the second thermoplastic resin layer of the second exterior material are facing each other.
11. The solid state battery according to claim 10, wherein said second thermoplastic resin layer of said first exterior material and said second thermoplastic resin layer of said second exterior material face each other. .
11. The solid state battery according to claim 10, wherein said first thermoplastic resin layer of said first exterior material and said first thermoplastic resin layer of said second exterior material face each other. .
The second thermoplastic resin layer of the first exterior material is directly bonded to one main surface of the conducting portion, and the second thermoplastic resin layer of the second exterior material is the other main surface of the conducting portion. 12. The solid state battery according to claim 10 or 11, which is bonded directly to the main surface of the .
The first thermoplastic resin layer of the first exterior material is directly bonded to one main surface of the conducting portion, and the first thermoplastic resin layer of the second exterior material is the other main surface of the conducting portion. 13. The solid state battery according to claim 10 or 12, wherein the solid state battery is bonded directly to the main surface of the .
The solid-state battery according to any one of claims 9 to 14, wherein the length of said overlapping region is at least 10% or more of the height of said battery element.
The solid-state battery according to any one of claims 9 to 15, wherein the overlap region is provided along the side surface of the battery element.
Claims 9 to 9, wherein at least the lead-out end of the conductive portion is provided on at least one of the upper surface side and the lower surface side of the battery element covered with the first exterior material or the second exterior material. 17. The solid battery according to any one of 16.
The solid-state battery according to any one of claims 9 to 17, wherein said conductive portion and said exterior composite extend in substantially the same direction as the extending direction of the contour surface of said battery element.
The solid-state battery according to any one of claims 6 to 8, wherein the sheathing material is composed of a continuous single structure, and the single structure surrounds the battery element.
The solid-state battery according to any one of claims 6 to 19, wherein the exterior material is provided along the contour surface of the battery element.
The solid-state battery according to any one of claims 6 to 20, wherein the lead-out portion of the conductive portion to the outside includes a bent portion.
An electronic device and an exterior material covering the electronic device,
The exterior material comprises a metal layer, a first thermoplastic resin layer located on the first main surface side of the metal layer, and a second thermoplastic resin layer located on the second main surface side of the metal layer. a layer and
An electronic device, wherein the melting point of the first thermoplastic resin layer and the melting point of the second thermoplastic resin layer are both higher than 260°C.